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Given x, y in mathbb{R}, and (x+y) + i = 3x + (x-y)i, find x and y.

💡To solve the equation ((x + y) + i = 3x + (x - y)i), I start by equating the real parts and the imaginary parts separately.First, I set the real parts equal to each other:[x + y = 3x]Simplifying this, I subtract (x) from both sides:[y = 2x]Next, I equate the imaginary parts:[1 = x - y]Substituting (y = 2x) into this equation, I get:[1 = x - 2x][1 = -x]Solving for (x), I find:[x = -1]Finally, substituting (x = -1) back into (y = 2x), I calculate:[y = 2(-1) = -2]Thus, the solutions are (x = -1) and (y = -2).

If m gt n, then the inequality that must hold is:A: 2m lt 3nB: 2+m gt 2+nC: 2-m gt 2-nD: frac{m}{2} lt frac{n}{2}

💡Okay, so I have this inequality problem here, and I need to figure out which of the options A, B, C, or D must hold true if m is greater than n. Let me try to understand each option one by one.First, the problem states that m > n. That means m is some number that's larger than n. It could be any numbers, positive or negative, as long as m is bigger than n. Okay, got that.Now, let's look at option A: 2m < 3n. Hmm, so if m is greater than n, does multiplying m by 2 and n by 3 necessarily make 2m less than 3n? I'm not sure. Maybe I should test this with some numbers to see if it always holds true or not.Let me pick m = 4 and n = 2 since 4 > 2. Plugging into option A: 2*4 = 8 and 3*2 = 6. So, 8 < 6? That's not true. So, in this case, option A doesn't hold. Maybe I should try another set of numbers to confirm.Let's try m = 5 and n = 1. Then 2*5 = 10 and 3*1 = 3. Is 10 < 3? No, that's also false. It seems like option A isn't necessarily true. Maybe it's not the right answer.Moving on to option B: 2 + m > 2 + n. Okay, so if m is greater than n, adding 2 to both m and n should preserve the inequality, right? Let me test it with the same numbers I used before.Using m = 4 and n = 2: 2 + 4 = 6 and 2 + 2 = 4. So, 6 > 4, which is true. Let's try another set: m = 5 and n = 1. 2 + 5 = 7 and 2 + 1 = 3. 7 > 3, which is also true. It seems like option B holds in these cases. Maybe B is the correct answer.But just to be thorough, let's check with negative numbers as well. Suppose m = -1 and n = -2. Since -1 > -2, let's see: 2 + (-1) = 1 and 2 + (-2) = 0. So, 1 > 0, which is true. Another example: m = 0 and n = -1. 2 + 0 = 2 and 2 + (-1) = 1. 2 > 1, which is true. It looks like option B works even with negative numbers.Okay, option B seems solid. But let's check the other options just to make sure.Option C: 2 - m > 2 - n. Hmm, so if m > n, what happens when we subtract them from 2? Let's test with m = 4 and n = 2. 2 - 4 = -2 and 2 - 2 = 0. So, -2 > 0? That's not true. Let's try another set: m = 5 and n = 1. 2 - 5 = -3 and 2 - 1 = 1. -3 > 1? No, that's also false. It seems like option C doesn't hold. Maybe it's the opposite?Wait, if m > n, then subtracting m would make it smaller, so 2 - m < 2 - n. Yeah, that makes sense. So, option C is actually the reverse of what it should be. So, C is incorrect.Now, option D: m/2 < n/2. If m > n, dividing both by 2 should preserve the inequality, right? Let's test it with m = 4 and n = 2. 4/2 = 2 and 2/2 = 1. So, 2 < 1? No, that's false. Another example: m = 6 and n = 3. 6/2 = 3 and 3/2 = 1.5. 3 < 1.5? No, that's also false. It seems like option D is incorrect as well.Wait a minute, if m > n, then dividing both by 2 should keep m/2 > n/2, not less than. So, option D is the opposite of what it should be. Therefore, D is incorrect.So, after testing all the options, only option B holds true in all the cases I tried. Options A, C, and D don't necessarily hold when m > n. Therefore, the correct answer must be option B.

overline{AB} is a diameter of circle omega. Tangents overline{AD} and overline{BC} are drawn so that overline{AC} and overline{BD} intersect at a point P on omega. A smaller circle eta is tangent to omega at P and also tangent to overline{AD} and overline{BC}. If overline{AD} = a and overline{BC} = b with a neq b, find the diameter of circle omega.A) a-bB) frac{1}{2}(a+b)C) sqrt{ab}D) frac{ab}{a+b}E) frac{1}{2}frac{ab}{a+b}

💡Okay, so I have this geometry problem here. Let me try to visualize it first. There's a circle ω with diameter AB. So, points A and B are at the ends of the diameter. Then, there are tangents AD and BC drawn from points A and B respectively. These tangents meet at some point outside the circle, but I think the key here is that lines AC and BD intersect at a point P, which lies on the circle ω. Additionally, there's a smaller circle η that is tangent to ω at point P and also tangent to the tangents AD and BC. The lengths of the tangents AD and BC are given as a and b respectively, and we need to find the diameter of the larger circle ω. The options are given, so that might help if I get stuck.First, let me recall some properties of circles and tangents. Since AD and BC are tangents from points A and B, their lengths are equal to the lengths of the tangents from those points to the circle. Wait, but in this case, AD and BC are tangents to the circle ω, right? So, the lengths AD and BC are the lengths of the tangents from A and B to the points of tangency D and C. I remember that the length of a tangent from a point to a circle is given by the square root of the square of the distance from the point to the center minus the square of the radius. But since AB is the diameter, the center of the circle ω is the midpoint of AB. Let me denote the center as O. So, if AB is the diameter, then AO = OB = radius of ω.Let me denote the radius of ω as R. So, AB = 2R. Now, the lengths of the tangents AD and BC can be expressed in terms of R. Since AD is a tangent from A to the circle, its length is sqrt(AO² - R²). Wait, but AO is equal to R because O is the center. So, AO = R, so AD = sqrt(R² - R²) = 0, which doesn't make sense. Hmm, I must have messed up.Wait, no. Actually, the tangent from a point outside the circle has length sqrt(d² - r²), where d is the distance from the point to the center, and r is the radius. But in this case, points A and B are on the circle, so the tangent from A to the circle would be zero length, which is not the case here. So, maybe D and C are points outside the circle, and AD and BC are tangents from A and B to some external points D and C.Wait, the problem says that AD and BC are tangents. So, points D and C must lie outside the circle ω, and AD and BC are tangent to ω. So, the lengths AD and BC are the lengths of the tangents from A and B to the circle ω. But since A and B are on the circle, the tangent from A would just be a line perpendicular to the radius at A, right? Similarly for B.Wait, that makes sense. So, the tangent at A is perpendicular to AB, and similarly, the tangent at B is perpendicular to AB. So, if AB is the diameter, then the tangents at A and B would be perpendicular to AB. So, if AB is horizontal, then the tangents at A and B would be vertical lines. But in the problem, it says that tangents AD and BC are drawn. So, points D and C are the points where these tangents meet some other lines or points.Wait, maybe I need to draw a diagram. Since I can't draw, I'll try to imagine it. Let me consider circle ω with diameter AB. Tangent at A is AD, and tangent at B is BC. These tangents meet at some external point, but in this case, lines AC and BD intersect at point P on ω. So, point P is the intersection of AC and BD, and it lies on the circle.Also, there's a smaller circle η tangent to ω at P and tangent to AD and BC. So, η is tangent to two lines AD and BC and tangent to the larger circle ω at P. So, η is a circle inside ω, tangent to it at P, and also tangent to the two tangents AD and BC.Given that AD = a and BC = b, with a ≠ b, we need to find the diameter of ω.Hmm, okay. Let me think about the properties of tangent circles and intersecting chords.Since P is the intersection of AC and BD, and P lies on ω, perhaps we can use some properties of intersecting chords or power of a point.Also, since η is tangent to ω at P, the center of η lies along the line connecting the centers of ω and η, which would be the line OP, where O is the center of ω.Additionally, since η is tangent to AD and BC, which are tangents to ω at A and B, perhaps there is some homothety or similarity involved.Wait, maybe I can use the power of point P with respect to ω. The power of P with respect to ω is zero since P lies on ω. But P is also the point where η is tangent to ω, so maybe there's a relation between the power of P with respect to η and ω.Alternatively, perhaps I can use coordinates. Let me set up a coordinate system. Let me place the circle ω with diameter AB on the x-axis, with center at the origin O(0,0). So, point A is (-R, 0) and point B is (R, 0), where R is the radius of ω, so diameter AB is 2R.The tangent at A is perpendicular to AB, so it's a vertical line. Since AB is horizontal, the tangent at A is vertical, so its equation is x = -R. Similarly, the tangent at B is x = R. Wait, but the problem says tangents AD and BC are drawn. So, points D and C must lie on these vertical tangents.Wait, if AD is the tangent at A, then D is a point on the tangent line at A, which is x = -R. Similarly, BC is the tangent at B, so C is a point on x = R. So, points D and C are somewhere along these vertical lines.Given that AD = a and BC = b, so the distance from A to D is a, and from B to C is b. Since A is (-R, 0), and the tangent at A is x = -R, moving up or down along this line, point D would be (-R, a) or (-R, -a). Similarly, point C would be (R, b) or (R, -b). Let's assume they are above the x-axis for simplicity, so D is (-R, a) and C is (R, b).Now, lines AC and BD intersect at point P on ω. Let me find the coordinates of P.First, let's find the equations of lines AC and BD.Point A is (-R, 0), and point C is (R, b). So, the slope of AC is (b - 0)/(R - (-R)) = b/(2R). So, the equation of AC is y = (b/(2R))(x + R).Similarly, point B is (R, 0), and point D is (-R, a). The slope of BD is (a - 0)/(-R - R) = a/(-2R) = -a/(2R). So, the equation of BD is y = (-a/(2R))(x - R).Now, let's find the intersection point P of AC and BD.Set the two equations equal:(b/(2R))(x + R) = (-a/(2R))(x - R)Multiply both sides by 2R to eliminate denominators:b(x + R) = -a(x - R)Expand both sides:bx + bR = -ax + aRBring all terms to one side:bx + ax + bR - aR = 0Factor:x(b + a) + R(b - a) = 0Solve for x:x = [R(a - b)] / (a + b)Now, plug this back into the equation of AC to find y:y = (b/(2R))(x + R) = (b/(2R))([R(a - b)/(a + b)] + R)Simplify inside the parentheses:[R(a - b)/(a + b) + R] = R[(a - b)/(a + b) + 1] = R[(a - b + a + b)/(a + b)] = R[2a/(a + b)] = 2aR/(a + b)So, y = (b/(2R)) * (2aR/(a + b)) = (b * 2aR) / (2R(a + b)) = (ab)/(a + b)Therefore, point P has coordinates:x = [R(a - b)] / (a + b)y = ab/(a + b)Now, since P lies on ω, which has equation x² + y² = R².So, plug in the coordinates of P into the circle equation:([R(a - b)/(a + b)]²) + (ab/(a + b))² = R²Let me compute each term:First term: [R²(a - b)²]/(a + b)²Second term: (a²b²)/(a + b)²So, adding them:[R²(a - b)² + a²b²]/(a + b)² = R²Multiply both sides by (a + b)²:R²(a - b)² + a²b² = R²(a + b)²Expand both sides:Left side: R²(a² - 2ab + b²) + a²b²Right side: R²(a² + 2ab + b²)Subtract left side from right side:R²(a² + 2ab + b²) - [R²(a² - 2ab + b²) + a²b²] = 0Simplify:R²(a² + 2ab + b² - a² + 2ab - b²) - a²b² = 0Simplify inside the brackets:R²(4ab) - a²b² = 0So:4abR² = a²b²Divide both sides by ab (since a ≠ 0 and b ≠ 0):4R² = abTherefore:R² = ab/4So, R = sqrt(ab)/2Therefore, the diameter AB is 2R = 2*(sqrt(ab)/2) = sqrt(ab)So, the diameter of circle ω is sqrt(ab), which is option C.**Final Answer**boxed{C}

Given a 3 times 3 grid, what is the maximum number of X's that can be placed such that no three X's align vertically, horizontally, or diagonally?text{(A)} 3 quad text{(B)} 4 quad text{(C)} 5 quad text{(D)} 6 quad text{(E)} 7text{(A)} 3 quad text{(B)} 4 quad text{(C)} 5 quad text{(D)} 6 quad text{(E)} 7

💡Okay, so I have this problem about a 3x3 grid, and I need to figure out the maximum number of X's I can place without having three in a row, column, or diagonal. Hmm, let me think about this step by step.First, I know that a 3x3 grid has 9 squares. The goal is to place as many X's as possible without getting three in a straight line. I remember this is similar to the game of tic-tac-toe, where you don't want your opponent to get three in a row. So, maybe some strategies from that game can help here.Let me visualize the grid:```1 2 34 5 67 8 9```Each number represents a position in the grid. Now, I need to place X's in these positions without having three in a line. Let's start by trying to place X's one by one and see where they can go without causing a three-in-a-row.If I place an X in position 1, then I can't place X's in positions 2 and 3 in the same row, or positions 4 and 7 in the same column, or positions 5 and 9 in the same diagonal. That seems restrictive. Maybe I should spread out the X's more.What if I place X's in positions 1, 5, and 9? Wait, that's the main diagonal, which would give me three in a row. That's not allowed. So, I need to avoid placing X's in all three positions of any diagonal, row, or column.Maybe I can place two X's in each row but in different columns and different diagonals. Let's try:- Place an X in position 1.- Then, in the second row, place an X in position 6.- In the third row, place an X in position 7.Now, let's check for any three in a row. The first column has X's in positions 1 and 4 (if I placed one there), but I didn't place an X in position 4. Wait, I only placed X's in positions 1, 6, and 7. That's only three X's, and none are in the same row, column, or diagonal. But I think I can place more.Let me try adding another X. If I place an X in position 3, does that cause any issues? Let's see:- Position 3 is in the first row, third column.- The first row now has X's in positions 1 and 3. That's okay because it's only two.- The third column has X's in positions 3 and 6. That's also two, which is fine.- Diagonally, position 3 doesn't align with any other X's.So now I have X's in positions 1, 3, 6, and 7. Let me check all rows, columns, and diagonals:- Rows: Each row has at most two X's.- Columns: Each column has at most two X's.- Diagonals: The main diagonal has X's in positions 1 and 7, but not 5. The other diagonal has X's in position 3, but not 5 or 7.Okay, that seems good. Can I add another X without causing three in a row? Let's try position 5. If I place an X in the center, does that create any three in a row?- The center is part of both diagonals, the middle row, and the middle column.- Currently, the middle row has an X in position 6, and the middle column has an X in position 3.- Placing an X in position 5 would make the middle row have X's in positions 5 and 6, which is fine.- The middle column would have X's in positions 3 and 5, which is also fine.- The diagonals would have X's in positions 1, 5, and 9 (if I had an X in 9), but I don't. Similarly, the other diagonal would have X's in positions 3, 5, and 7, but I only have X's in 3 and 7.Wait, if I place an X in position 5, then positions 3, 5, and 7 would form a diagonal. But I already have X's in 3 and 7. So adding an X in 5 would create three in a diagonal. That's not allowed. So I can't place an X in position 5.What about position 2? Let's try placing an X there.- Position 2 is in the first row, second column.- The first row already has X's in positions 1 and 3. Adding position 2 would make three in the first row. That's not allowed.How about position 4? Let's see:- Position 4 is in the second row, first column.- The second row has an X in position 6. Adding position 4 would make two in the second row, which is fine.- The first column has an X in position 1. Adding position 4 would make two in the first column, which is fine.- Diagonally, position 4 doesn't align with any other X's.So, placing an X in position 4 seems okay. Now I have X's in positions 1, 3, 4, 6, and 7. Let me check again:- Rows: First row has X's in 1 and 3; second row has X's in 4 and 6; third row has X in 7. All rows have at most two X's.- Columns: First column has X's in 1 and 4; second column has X in 6; third column has X in 3 and 7. All columns have at most two X's.- Diagonals: Main diagonal has X's in 1 and 7; other diagonal has X's in 3 and 4. No three in a diagonal.Okay, that seems good. Can I add another X? Let's try position 8.- Position 8 is in the third row, second column.- The third row has an X in position 7. Adding position 8 would make two in the third row, which is fine.- The second column has an X in position 6. Adding position 8 would make two in the second column, which is fine.- Diagonally, position 8 doesn't align with any other X's.So, placing an X in position 8 is okay. Now I have X's in positions 1, 3, 4, 6, 7, and 8. Let me check:- Rows: First row has two X's; second row has two X's; third row has two X's. All good.- Columns: First column has two X's; second column has two X's; third column has two X's. All good.- Diagonals: Main diagonal has two X's; other diagonal has two X's. No three in a diagonal.Wait, but I have six X's now. Is that possible? Let me double-check for any three in a row.Looking at the grid:```X X XX X XX X X```Wait, no, that's all X's. But I only placed X's in positions 1, 3, 4, 6, 7, and 8. So the grid looks like:```X XX X X X```Wait, no, that's not correct. Let me map it properly:- Position 1: X- Position 3: X- Position 4: X- Position 6: X- Position 7: X- Position 8: XSo the grid is:```X XX XX X```Wait, actually, position 7 is in the third row, first column, and position 8 is in the third row, second column. So the third row has X's in positions 7 and 8, which is two X's, not three. Similarly, the first row has X's in positions 1 and 3, which is two. The second row has X's in positions 4 and 6, which is two. Columns: first column has X's in 1 and 4; second column has X's in 6 and 8; third column has X's in 3 and 7. Diagonals: main diagonal has X's in 1 and 7; other diagonal has X's in 3 and 4. So no three in a row anywhere.Wait, but I thought the maximum was 6, but the options only go up to 7. Hmm, maybe I made a mistake. Let me try adding another X.If I try to place an X in position 2, which is in the first row, second column. The first row already has X's in 1 and 3, so adding position 2 would make three in the first row. Not allowed.What about position 5? If I place an X in the center, position 5, does that create any three in a row?- The center is part of both diagonals, the middle row, and the middle column.- Currently, the middle row has X's in positions 4 and 6. Adding position 5 would make three in the middle row. Not allowed.- Similarly, the middle column has X's in positions 6 and 8. Adding position 5 would make three in the middle column. Not allowed.- Diagonals: Adding position 5 would create three in the diagonal from 3 to 5 to 7, but I only have X's in 3 and 7. So that would make three in a diagonal. Not allowed.So I can't place an X in position 5.What about position 9? Let's try placing an X there.- Position 9 is in the third row, third column.- The third row has X's in positions 7 and 8. Adding position 9 would make three in the third row. Not allowed.So I can't place an X in position 9.Wait, so I have six X's and can't add any more without violating the three-in-a-row rule. But the options don't have 6 as the answer. Wait, let me check the options again.The options are: (A) 3, (B) 4, (C) 5, (D) 6, (E) 7.Oh, option D is 6. So maybe 6 is possible. But I thought the maximum was 5. Maybe I was wrong earlier.Wait, let me try another arrangement. Maybe I can place seven X's without three in a row. Let's see.If I place X's in all positions except the center, that's eight X's. But that would definitely have three in a row. So that's not allowed.What if I leave out two positions? Let's say I leave out position 5 and position 9. Then I have seven X's. Let's see:```X X XX XX X```Wait, that's seven X's. Let me check for three in a row.- Rows: First row has three X's. That's not allowed. So that doesn't work.What if I leave out position 5 and position 1? Then I have seven X's:``` X XX XX X X```Again, the third row has three X's. Not allowed.Hmm, maybe it's impossible to have seven X's without three in a row. So the maximum must be six.Wait, but earlier I thought six was possible, but I'm not sure. Let me try another arrangement.What if I place X's in positions 1, 2, 4, 6, 8, and 9. Let's see:```X XX X X X```Wait, that's not correct. Let me map it properly:- Position 1: X- Position 2: X- Position 4: X- Position 6: X- Position 8: X- Position 9: XSo the grid is:```X XX X X X```Wait, the first row has two X's, the second row has two X's, and the third row has two X's. Columns:- First column: X in 1 and 4- Second column: X in 2 and 8- Third column: X in 6 and 9Diagonals:- Main diagonal: X in 1 and 9- Other diagonal: X in 2 and 6So no three in a row anywhere. That seems to work. So six X's are possible.Wait, but earlier I thought six was possible, but I'm not sure if that's the maximum. Let me try adding another X.If I try to place an X in position 5, the center, does that create three in a row?- The center is part of both diagonals, the middle row, and the middle column.- Currently, the middle row has X's in positions 4 and 6. Adding position 5 would make three in the middle row. Not allowed.- Similarly, the middle column has X's in positions 2 and 8. Adding position 5 would make three in the middle column. Not allowed.- Diagonals: Adding position 5 would create three in the diagonal from 1 to 5 to 9, but I only have X's in 1 and 9. So that would make three in a diagonal. Not allowed.So I can't place an X in position 5.What about position 3? If I place an X there, does it create three in a row?- Position 3 is in the first row, third column.- The first row already has X's in positions 1 and 2. Adding position 3 would make three in the first row. Not allowed.So I can't place an X in position 3.What about position 7? If I place an X there, does it create three in a row?- Position 7 is in the third row, first column.- The third row has X's in positions 8 and 9. Adding position 7 would make three in the third row. Not allowed.So I can't place an X in position 7.Wait, so with six X's, I can't add any more without violating the three-in-a-row rule. So six seems to be the maximum.But I'm a bit confused because I thought the answer was five. Maybe I was wrong earlier. Let me check some references or think about it differently.I remember that in a 3x3 grid, the maximum number of X's without three in a row is six. This is because you can place two X's in each row and column without aligning three. So, yes, six should be possible.Wait, but in my earlier arrangement, I had six X's without any three in a row. So maybe the answer is six.But let me try another arrangement to confirm. Let's place X's in positions 1, 2, 4, 6, 8, and 9 again:```X XX X X X```Checking rows, columns, and diagonals:- Rows: Each has two X's.- Columns: Each has two X's.- Diagonals: Each has two X's.No three in a row anywhere. So six is possible.Wait, but I also tried placing X's in positions 1, 3, 4, 6, 7, and 8 earlier, which also worked. So six seems to be achievable.Therefore, the maximum number of X's that can be placed without three in a row is six.Wait, but the options are up to seven, and I thought seven was possible, but it seems not. So I think the answer is six, which is option D.But let me double-check. If I try to place seven X's, is it possible without three in a row?Let's say I leave out position 5 and position 9. Then I have seven X's:```X X XX XX X```But the first row has three X's. Not allowed.What if I leave out position 5 and position 1? Then I have seven X's:``` X XX XX X X```The third row has three X's. Not allowed.What if I leave out position 5 and position 3? Then I have seven X's:```X XX XX X X```The third row has three X's. Not allowed.Hmm, seems like any arrangement with seven X's would result in three in a row somewhere. So six is indeed the maximum.Therefore, the answer should be six, which is option D.

The distance from the focus of the parabola y^2 = 8x to the directrix is (  )A: 1 B: 2 C: 4 D: 8

💡Okay, so I have this problem here: "The distance from the focus of the parabola ( y^2 = 8x ) to the directrix is (  )" with options A: 1, B: 2, C: 4, D: 8. Hmm, I need to figure out which one is correct. I remember that for a parabola, the distance from the focus to the directrix is related to the parameter of the parabola, but I'm a bit fuzzy on the exact details. Let me think through this step by step.First, I recall that the standard form of a parabola that opens to the right is ( y^2 = 4px ), where ( p ) is the distance from the vertex to the focus (and also from the vertex to the directrix). So, comparing this with the given equation ( y^2 = 8x ), I can see that ( 4p = 8 ). Solving for ( p ), I divide both sides by 4, which gives ( p = 2 ). Wait, so if ( p = 2 ), that means the focus is 2 units to the right of the vertex, and the directrix is 2 units to the left of the vertex. But the question is asking for the distance from the focus to the directrix, not just the distance from the vertex. So, if the focus is 2 units to the right and the directrix is 2 units to the left, the total distance between them should be the sum of these two distances, right? That would be ( 2 + 2 = 4 ). Let me visualize this. The vertex of the parabola is at the origin (0,0). The focus is at (2,0), and the directrix is the vertical line ( x = -2 ). So, the distance from the focus (2,0) to the directrix ( x = -2 ) is the horizontal distance between these two points. Since the directrix is a vertical line, the distance from any point to it is just the absolute difference in the x-coordinates. So, the distance would be ( |2 - (-2)| = |4| = 4 ). Hmm, that seems to make sense. So, the distance from the focus to the directrix is 4 units. Looking back at the options, C is 4, so that must be the correct answer. But just to make sure I didn't make a mistake, let me double-check. The standard form is ( y^2 = 4px ), so ( 4p = 8 ) gives ( p = 2 ). The focus is at (p,0) which is (2,0), and the directrix is ( x = -p ) which is ( x = -2 ). The distance between (2,0) and the line ( x = -2 ) is indeed 4 units. I think that's solid. I don't see any errors in my reasoning. So, yeah, the answer should be C: 4.**Final Answer**boxed{C}

Given ( a ) and ( b ) are non-zero positive numbers and ( x > 1 ) satisfy the equation ( 9(log_a x)^2 + 5(log_b x)^2 = 17 ), find `a` and `b` knowing that ( log_a b cdot log_b a = 2 ).A) ( a = 10, b = 10^{sqrt{2}} )B) ( a = 10^{sqrt{2}}, b = 10 )C) ( a = 10^2, b = 10^3 )D) ( a = 10^3, b = 10^2 )

💡Okay, so I have this problem where I need to find the values of ( a ) and ( b ) given some logarithmic equations. Let me try to break it down step by step.First, the problem states that ( a ) and ( b ) are non-zero positive numbers, and ( x > 1 ) satisfies the equation:[ 9(log_a x)^2 + 5(log_b x)^2 = 17 ]Additionally, we know that:[ log_a b cdot log_b a = 2 ]Hmm, I remember that logarithms have some reciprocal properties. Specifically, ( log_a b ) is the reciprocal of ( log_b a ). So, if I let ( log_a b = k ), then ( log_b a = frac{1}{k} ). Therefore, their product would be:[ k cdot frac{1}{k} = 1 ]But wait, the problem says their product is 2, not 1. That seems contradictory. Maybe I'm missing something here.Let me write down what I know:1. ( log_a b cdot log_b a = 2 )2. ( 9(log_a x)^2 + 5(log_b x)^2 = 17 )I think I need to express everything in terms of a common base to simplify. Let me choose base 10 for simplicity, since the answer choices involve powers of 10.Using the change of base formula:[ log_a x = frac{log x}{log a} ][ log_b x = frac{log x}{log b} ]So, substituting these into the equation:[ 9left(frac{log x}{log a}right)^2 + 5left(frac{log x}{log b}right)^2 = 17 ]Let me factor out ( (log x)^2 ):[ (log x)^2 left( frac{9}{(log a)^2} + frac{5}{(log b)^2} right) = 17 ]Since ( x > 1 ), ( log x ) is positive, so I can divide both sides by ( (log x)^2 ):[ frac{9}{(log a)^2} + frac{5}{(log b)^2} = frac{17}{(log x)^2} ]Hmm, but I don't know ( log x ). Maybe I can find a relationship between ( log a ) and ( log b ) from the other equation.From ( log_a b cdot log_b a = 2 ), using the change of base formula again:[ log_a b = frac{log b}{log a} ][ log_b a = frac{log a}{log b} ]Multiplying them together:[ frac{log b}{log a} cdot frac{log a}{log b} = 1 ]But the problem says this product is 2, which is a contradiction because it should be 1. Maybe I made a mistake.Wait, perhaps the problem is written differently. Let me check again. It says ( log_a b cdot log_b a = 2 ). But as I just calculated, this should be 1. Maybe there's a typo or I'm misunderstanding the notation.Alternatively, perhaps the logs are not base 10? But the answer choices are in base 10, so maybe I need to consider another approach.Let me denote ( u = log_a x ) and ( v = log_b x ). Then the equation becomes:[ 9u^2 + 5v^2 = 17 ]Also, from the logarithmic identity:[ log_a b = frac{log b}{log a} ][ log_b a = frac{log a}{log b} ]So their product is:[ frac{log b}{log a} cdot frac{log a}{log b} = 1 ]But the problem states it's 2, so this is confusing. Maybe there's an error in the problem statement? Or perhaps I need to interpret it differently.Wait, maybe ( log_a b ) and ( log_b a ) are not reciprocals? No, that's a fundamental property of logarithms. So if their product is 2, that would mean:[ frac{log b}{log a} cdot frac{log a}{log b} = 1 = 2 ]Which is impossible. Therefore, there must be a misunderstanding.Alternatively, perhaps the logs are not in the same base? But the problem doesn't specify, so I assume they are in the same base. Maybe I need to consider a different approach.Let me try to express ( log_a x ) and ( log_b x ) in terms of each other. Let me denote ( k = log_a b ), so ( log_b a = frac{1}{k} ). Then, from the given condition:[ k cdot frac{1}{k} = 1 = 2 ]Again, this is a contradiction. So perhaps the problem has a typo, or I'm missing something.Wait, maybe the logs are not in base 10 but in another base, say base ( a ) or base ( b ). Let me try that.If I consider ( log_a b ) and ( log_b a ), regardless of the base, their product is always 1. So if the problem says it's 2, that's impossible. Therefore, perhaps the problem is miswritten, or I'm misinterpreting it.Alternatively, maybe the logs are not in the same base. For example, ( log_a b ) is in base ( a ), and ( log_b a ) is in base ( b ). But as I know, ( log_a b = frac{1}{log_b a} ), so their product is 1. So again, the product being 2 is impossible.Wait, maybe the logs are in different bases, not related to ( a ) and ( b ). For example, ( log_a b ) is in base 10, and ( log_b a ) is in base 2. But that would complicate things, and the answer choices are in base 10.I'm stuck here. Maybe I should try to proceed with the assumption that the product is 1, even though the problem says 2. Let me see where that leads.If ( log_a b cdot log_b a = 1 ), then as before, ( frac{log b}{log a} cdot frac{log a}{log b} = 1 ). So that's consistent.But the problem says it's 2, so maybe I need to adjust my approach. Perhaps the logs are in a different base, say base ( c ), and ( c ) is not 10. Let me denote ( log_c a = m ) and ( log_c b = n ). Then:[ log_a b = frac{log_c b}{log_c a} = frac{n}{m} ][ log_b a = frac{log_c a}{log_c b} = frac{m}{n} ]So their product is:[ frac{n}{m} cdot frac{m}{n} = 1 ]Again, it's 1, not 2. So I'm back to the same contradiction.Wait, maybe the logs are in base ( x )? Let me try that. If ( log_a b ) is in base ( x ), then:[ log_a b = frac{log_x b}{log_x a} ]Similarly, ( log_b a = frac{log_x a}{log_x b} )So their product is:[ frac{log_x b}{log_x a} cdot frac{log_x a}{log_x b} = 1 ]Still 1. So regardless of the base, the product is 1. Therefore, the problem must have a typo, or I'm misinterpreting it.Alternatively, maybe the logs are not in the same base. For example, ( log_a b ) is in base 10, and ( log_b a ) is in base ( e ). But that would complicate things, and the answer choices are in base 10.Wait, perhaps the logs are in base ( a ) and base ( b ) respectively, but that still leads to their product being 1.I'm really confused here. Maybe I should proceed with the given condition, assuming it's correct, and see if I can find a solution.Let me denote ( log_a b = k ), so ( log_b a = frac{1}{k} ). Then, from the given condition:[ k cdot frac{1}{k} = 1 = 2 ]Which is impossible. Therefore, perhaps the problem is miswritten, or I'm misinterpreting it.Alternatively, maybe the logs are in different bases, say base 10 and base ( e ). Let me try that.Let ( log_a b ) be in base 10, so:[ log_{10} b / log_{10} a ]And ( log_b a ) in base ( e ), so:[ ln a / ln b ]Then their product is:[ left( frac{log_{10} b}{log_{10} a} right) cdot left( frac{ln a}{ln b} right) ]But this is complicated and doesn't simplify easily. I don't think this is the right approach.Wait, maybe the logs are in the same base, say base 10, but the product is 2. So:[ left( frac{log b}{log a} right) cdot left( frac{log a}{log b} right) = 1 = 2 ]Still impossible. Therefore, I think there must be a typo in the problem, or I'm missing something.Alternatively, maybe the logs are in base ( a ) and base ( b ), but with a different interpretation. Let me think.Wait, maybe the logs are in base ( a ) and base ( b ), but the product is 2. So:[ log_a b cdot log_b a = 2 ]But as I know, ( log_a b = frac{1}{log_b a} ), so:[ frac{1}{log_b a} cdot log_b a = 1 = 2 ]Again, impossible.I'm really stuck here. Maybe I should try to proceed with the given equation and see if I can find a relationship between ( a ) and ( b ) without using the logarithmic identity.From the equation:[ 9(log_a x)^2 + 5(log_b x)^2 = 17 ]Let me express ( log_a x ) and ( log_b x ) in terms of ( log x ):[ log_a x = frac{log x}{log a} ][ log_b x = frac{log x}{log b} ]Substituting back:[ 9left( frac{log x}{log a} right)^2 + 5left( frac{log x}{log b} right)^2 = 17 ]Let me factor out ( (log x)^2 ):[ (log x)^2 left( frac{9}{(log a)^2} + frac{5}{(log b)^2} right) = 17 ]Since ( x > 1 ), ( log x ) is positive, so I can divide both sides by ( (log x)^2 ):[ frac{9}{(log a)^2} + frac{5}{(log b)^2} = frac{17}{(log x)^2} ]But I don't know ( log x ). Maybe I can find a relationship between ( log a ) and ( log b ) from the other equation.Wait, the other equation is ( log_a b cdot log_b a = 2 ). As I tried earlier, this seems impossible because their product should be 1. Maybe I need to consider that ( log_a b ) and ( log_b a ) are not reciprocals, but that contradicts the logarithmic identity.Alternatively, maybe the logs are in different bases, but I can't see how that would make their product 2.Wait, perhaps the logs are in base ( x ). Let me try that.If ( log_a b ) is in base ( x ), then:[ log_a b = frac{log_x b}{log_x a} ]Similarly, ( log_b a = frac{log_x a}{log_x b} )So their product is:[ frac{log_x b}{log_x a} cdot frac{log_x a}{log_x b} = 1 ]Again, it's 1, not 2.I'm really stuck. Maybe I should look at the answer choices and see if any of them satisfy the given conditions, even if it means ignoring the contradiction.Looking at the options:A) ( a = 10, b = 10^{sqrt{2}} )B) ( a = 10^{sqrt{2}}, b = 10 )C) ( a = 10^2, b = 10^3 )D) ( a = 10^3, b = 10^2 )Let me test option B: ( a = 10^{sqrt{2}}, b = 10 )First, check ( log_a b cdot log_b a ):[ log_{10^{sqrt{2}}} 10 cdot log_{10} 10^{sqrt{2}} ][ = frac{log 10}{log 10^{sqrt{2}}} cdot frac{log 10^{sqrt{2}}}{log 10} ][ = frac{1}{sqrt{2}} cdot sqrt{2} = 1 ]But the problem says it should be 2. So this doesn't work.Wait, maybe I made a mistake in calculation.Wait, ( log_{10^{sqrt{2}}} 10 = frac{log 10}{log 10^{sqrt{2}}} = frac{1}{sqrt{2}} )And ( log_{10} 10^{sqrt{2}} = sqrt{2} )So their product is ( frac{1}{sqrt{2}} cdot sqrt{2} = 1 ), which is correct. But the problem says it's 2, so this option doesn't satisfy the condition.Wait, maybe I need to consider that the logs are in different bases. Let me try option A: ( a = 10, b = 10^{sqrt{2}} )Then, ( log_{10} 10^{sqrt{2}} = sqrt{2} )And ( log_{10^{sqrt{2}}} 10 = frac{1}{sqrt{2}} )Their product is ( sqrt{2} cdot frac{1}{sqrt{2}} = 1 ), again not 2.Hmm, none of the options seem to satisfy the condition ( log_a b cdot log_b a = 2 ). Maybe I'm misunderstanding the problem.Wait, perhaps the logs are in base ( a ) and base ( b ), but the product is 2. So, ( log_a b cdot log_b a = 2 ). But as I know, ( log_a b = frac{1}{log_b a} ), so their product is 1. Therefore, the problem must have a typo.Alternatively, maybe the logs are in base ( x ), and ( x ) is such that the product is 2. Let me try that.If ( log_a b cdot log_b a = 2 ), and both logs are in base ( x ), then:[ frac{log_x b}{log_x a} cdot frac{log_x a}{log_x b} = 1 = 2 ]Again, impossible.I'm really stuck here. Maybe I should try to solve the equation without considering the logarithmic identity, assuming it's a typo.From the equation:[ 9(log_a x)^2 + 5(log_b x)^2 = 17 ]Let me express ( log_a x ) and ( log_b x ) in terms of ( log x ):[ log_a x = frac{log x}{log a} ][ log_b x = frac{log x}{log b} ]Substituting back:[ 9left( frac{log x}{log a} right)^2 + 5left( frac{log x}{log b} right)^2 = 17 ]Let me denote ( u = frac{log x}{log a} ) and ( v = frac{log x}{log b} ). Then the equation becomes:[ 9u^2 + 5v^2 = 17 ]I also know that ( u ) and ( v ) are related through ( log a ) and ( log b ). Let me express ( v ) in terms of ( u ):[ v = frac{log x}{log b} = frac{log x}{log a} cdot frac{log a}{log b} = u cdot frac{log a}{log b} ]Let me denote ( k = frac{log a}{log b} ), so ( v = u cdot k ). Substituting back into the equation:[ 9u^2 + 5(u cdot k)^2 = 17 ][ 9u^2 + 5k^2 u^2 = 17 ][ u^2 (9 + 5k^2) = 17 ][ u^2 = frac{17}{9 + 5k^2} ]But I don't know ( k ). However, from the other condition, which I think is a typo, but let's assume it's supposed to be 1. So:[ log_a b cdot log_b a = 1 ]Which implies ( k cdot frac{1}{k} = 1 ), which is consistent.But since the problem says it's 2, maybe ( k cdot frac{1}{k} = 2 ), which is impossible. Therefore, I think the problem has a typo, and the correct product should be 1.Assuming that, then ( k ) can be any value, but we need to find ( a ) and ( b ) such that the equation holds. Let me look at the answer choices again.Option B: ( a = 10^{sqrt{2}}, b = 10 )Let me check if this satisfies the equation:First, ( log_a x = frac{log x}{log 10^{sqrt{2}}} = frac{log x}{sqrt{2} log 10} = frac{log x}{sqrt{2}} )Similarly, ( log_b x = frac{log x}{log 10} = log x )Substituting into the equation:[ 9left( frac{log x}{sqrt{2}} right)^2 + 5(log x)^2 = 17 ][ 9 cdot frac{(log x)^2}{2} + 5(log x)^2 = 17 ][ frac{9}{2}(log x)^2 + 5(log x)^2 = 17 ][ left( frac{9}{2} + 5 right)(log x)^2 = 17 ][ left( frac{9}{2} + frac{10}{2} right)(log x)^2 = 17 ][ frac{19}{2}(log x)^2 = 17 ][ (log x)^2 = frac{34}{19} ][ log x = sqrt{frac{34}{19}} ]Which is a valid solution since ( x > 1 ).Therefore, option B seems to satisfy the equation, even though the logarithmic product condition seems contradictory. Maybe the problem intended the product to be 1, and there was a typo.Alternatively, perhaps I made a mistake in interpreting the logs. Let me check again.If ( a = 10^{sqrt{2}} ) and ( b = 10 ), then:[ log_a b = log_{10^{sqrt{2}}} 10 = frac{log 10}{log 10^{sqrt{2}}} = frac{1}{sqrt{2}} ][ log_b a = log_{10} 10^{sqrt{2}} = sqrt{2} ]Their product is ( frac{1}{sqrt{2}} cdot sqrt{2} = 1 ), which contradicts the given condition of 2. Therefore, option B doesn't satisfy the logarithmic product condition.Wait, but the equation does hold. So maybe the problem has a typo, and the correct product should be 1. In that case, option B would be correct.Alternatively, maybe I need to consider that the logs are in different bases. Let me try option C: ( a = 10^2, b = 10^3 )Then:[ log_a b = log_{10^2} 10^3 = frac{3}{2} ][ log_b a = log_{10^3} 10^2 = frac{2}{3} ]Their product is ( frac{3}{2} cdot frac{2}{3} = 1 ), again not 2.Option D: ( a = 10^3, b = 10^2 )Then:[ log_a b = log_{10^3} 10^2 = frac{2}{3} ][ log_b a = log_{10^2} 10^3 = frac{3}{2} ]Their product is ( frac{2}{3} cdot frac{3}{2} = 1 ), still not 2.So none of the options satisfy the logarithmic product condition of 2. Therefore, I think there must be a typo in the problem, and the correct product should be 1. In that case, option B would be the correct answer because it satisfies the equation.Alternatively, maybe the logs are in base ( x ), and ( x ) is such that the product is 2. Let me try that.If ( log_a b cdot log_b a = 2 ), and both logs are in base ( x ), then:[ frac{log_x b}{log_x a} cdot frac{log_x a}{log_x b} = 1 = 2 ]Again, impossible.I'm really stuck here. Maybe I should conclude that there's a typo in the problem, and the correct answer is option B, assuming the product should be 1.

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