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If `alpha` and `beta` are sum and product of non zero solution of the equation `overline (z)^2 + |z| = 0` where z is a complex number then value of `4(alpha^2 + beta^2)` is equal to

A

2

B

6

C

4

D

8

Text Solution

AI Generated Solution

The correct Answer is:
To solve the equation \( \overline{z}^2 + |z| = 0 \) where \( z \) is a complex number, we will follow these steps: ### Step 1: Express \( z \) in terms of its real and imaginary parts Let \( z = x + iy \), where \( x \) and \( y \) are real numbers. The conjugate of \( z \) is given by: \[ \overline{z} = x - iy \] ### Step 2: Substitute \( \overline{z} \) and \( |z| \) into the equation The modulus \( |z| \) is given by: \[ |z| = \sqrt{x^2 + y^2} \] Substituting these into the equation: \[ (x - iy)^2 + \sqrt{x^2 + y^2} = 0 \] ### Step 3: Expand \( (x - iy)^2 \) Calculating \( (x - iy)^2 \): \[ (x - iy)^2 = x^2 - 2xyi - y^2 = (x^2 - y^2) - 2xyi \] Thus, the equation becomes: \[ (x^2 - y^2) - 2xyi + \sqrt{x^2 + y^2} = 0 \] ### Step 4: Separate the real and imaginary parts For the equation to hold, both the real part and the imaginary part must equal zero: 1. Real part: \[ x^2 - y^2 + \sqrt{x^2 + y^2} = 0 \] 2. Imaginary part: \[ -2xy = 0 \] ### Step 5: Solve the imaginary part From \( -2xy = 0 \), we have two cases: - Case 1: \( x = 0 \) - Case 2: \( y = 0 \) ### Step 6: Analyze each case **Case 1: \( x = 0 \)** Substituting \( x = 0 \) into the real part: \[ 0 - y^2 + \sqrt{0 + y^2} = 0 \implies -y^2 + |y| = 0 \] This gives: \[ |y| = y^2 \] Thus, \( y = 1 \) or \( y = -1 \). Therefore, the solutions are \( z = i \) and \( z = -i \). **Case 2: \( y = 0 \)** Substituting \( y = 0 \) into the real part: \[ x^2 - 0 + |x| = 0 \implies x^2 + |x| = 0 \] This implies \( x = 0 \) (since \( x \) cannot be negative). Thus, this case does not yield any non-zero solutions. ### Step 7: Identify non-zero solutions The non-zero solutions from Case 1 are: - \( z = i \) (where \( x = 0, y = 1 \)) - \( z = -i \) (where \( x = 0, y = -1 \)) ### Step 8: Calculate \( \alpha \) and \( \beta \) Let: - \( \alpha \) be the sum of the solutions: \[ \alpha = i + (-i) = 0 \] - \( \beta \) be the product of the solutions: \[ \beta = i \cdot (-i) = 1 \] ### Step 9: Calculate \( 4(\alpha^2 + \beta^2) \) Now, we compute: \[ \alpha^2 = 0^2 = 0 \] \[ \beta^2 = 1^2 = 1 \] Thus, \[ 4(\alpha^2 + \beta^2) = 4(0 + 1) = 4 \] ### Final Answer The value of \( 4(\alpha^2 + \beta^2) \) is \( \boxed{4} \).
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