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If |z1| and |z2| are the distance of po...

If `|z_1|` and `|z_2|` are the distance of points on the curve `5zbarz-2i(z^2-barz^2)-9=0` which are at maximum and minimum distance from the origin, then the value of `|z_1|+|z_2|` is equal to :

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To solve the problem, we need to analyze the curve given by the equation: \[ 5z \bar{z} - 2i(z^2 - \bar{z}^2) - 9 = 0 \] ### Step 1: Rewrite the equation using polar coordinates Let \( z = re^{i\theta} \), where \( r = |z| \) (the modulus of \( z \)) and \( \theta \) is the argument of \( z \). Then, we have: - \( \bar{z} = re^{-i\theta} \) - \( z \bar{z} = r^2 \) - \( z^2 = r^2 e^{2i\theta} \) - \( \bar{z}^2 = r^2 e^{-2i\theta} \) Substituting these into the equation gives: \[ 5r^2 - 2i(r^2 e^{2i\theta} - r^2 e^{-2i\theta}) - 9 = 0 \] ### Step 2: Simplify the equation The term \( e^{2i\theta} - e^{-2i\theta} \) can be simplified using the sine function: \[ e^{2i\theta} - e^{-2i\theta} = 2i \sin(2\theta) \] Thus, the equation becomes: \[ 5r^2 - 2i(-2ir^2 \sin(2\theta)) - 9 = 0 \] This simplifies to: \[ 5r^2 + 4r^2 \sin(2\theta) - 9 = 0 \] ### Step 3: Rearranging the equation Rearranging gives: \[ 5r^2 + 4r^2 \sin(2\theta) = 9 \] Factoring out \( r^2 \): \[ r^2(5 + 4 \sin(2\theta)) = 9 \] ### Step 4: Solve for \( r^2 \) Now, we can express \( r^2 \): \[ r^2 = \frac{9}{5 + 4 \sin(2\theta)} \] ### Step 5: Determine the maximum and minimum values of \( r \) To find the maximum and minimum values of \( r \), we need to analyze the expression \( 5 + 4 \sin(2\theta) \). The sine function \( \sin(2\theta) \) varies between -1 and 1. Therefore: - Maximum value of \( 5 + 4 \sin(2\theta) \) occurs when \( \sin(2\theta) = 1 \): \[ 5 + 4(1) = 9 \] - Minimum value of \( 5 + 4 \sin(2\theta) \) occurs when \( \sin(2\theta) = -1 \): \[ 5 + 4(-1) = 1 \] ### Step 6: Calculate \( r^2 \) for maximum and minimum 1. For maximum \( 5 + 4 \sin(2\theta) = 9 \): \[ r^2 = \frac{9}{9} = 1 \] \[ r = 1 \] 2. For minimum \( 5 + 4 \sin(2\theta) = 1 \): \[ r^2 = \frac{9}{1} = 9 \] \[ r = 3 \] ### Step 7: Find \( |z_1| + |z_2| \) Now, we have: - \( |z_1| = 1 \) (minimum distance) - \( |z_2| = 3 \) (maximum distance) Thus, the value of \( |z_1| + |z_2| \) is: \[ |z_1| + |z_2| = 1 + 3 = 4 \] ### Final Answer The value of \( |z_1| + |z_2| \) is \( \boxed{4} \). ---
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