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The square roots of - 2 + 2 sqrt(3)i ar...

The square roots of `- 2 + 2 sqrt(3)i` are :

A

`pm (1 + sqrt(3)i)`

B

`pm (1 - sqrt(3)i)`

C

`pm (-1 + sqrt(3)i)`

D

None of these

Text Solution

AI Generated Solution

The correct Answer is:
To find the square roots of the complex number \(-2 + 2\sqrt{3}i\), we can express it in the form \(a + bi\) where \(a\) and \(b\) are real numbers. We will find \(x\) and \(y\) such that: \[ x^2 - y^2 = -2 \quad (1) \] \[ 2xy = 2\sqrt{3} \quad (2) \] ### Step 1: Solve for \(xy\) From equation (2), we can simplify it to: \[ xy = \sqrt{3} \quad (3) \] ### Step 2: Express \(y\) in terms of \(x\) From equation (3), we can express \(y\) in terms of \(x\): \[ y = \frac{\sqrt{3}}{x} \quad (4) \] ### Step 3: Substitute \(y\) in equation (1) Now, substitute equation (4) into equation (1): \[ x^2 - \left(\frac{\sqrt{3}}{x}\right)^2 = -2 \] This simplifies to: \[ x^2 - \frac{3}{x^2} = -2 \] ### Step 4: Multiply through by \(x^2\) To eliminate the fraction, multiply through by \(x^2\): \[ x^4 + 2x^2 - 3 = 0 \] ### Step 5: Let \(u = x^2\) Let \(u = x^2\). Then we have a quadratic equation: \[ u^2 + 2u - 3 = 0 \] ### Step 6: Solve the quadratic equation Using the quadratic formula \(u = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\): \[ u = \frac{-2 \pm \sqrt{2^2 - 4 \cdot 1 \cdot (-3)}}{2 \cdot 1} \] \[ u = \frac{-2 \pm \sqrt{4 + 12}}{2} \] \[ u = \frac{-2 \pm \sqrt{16}}{2} \] \[ u = \frac{-2 \pm 4}{2} \] This gives us: \[ u = 1 \quad \text{or} \quad u = -3 \] Since \(u = x^2\), we discard \(u = -3\) (as \(x^2\) cannot be negative). ### Step 7: Find \(x\) Thus, we have: \[ x^2 = 1 \implies x = \pm 1 \] ### Step 8: Find \(y\) Substituting \(x\) back into equation (4): For \(x = 1\): \[ y = \frac{\sqrt{3}}{1} = \sqrt{3} \] For \(x = -1\): \[ y = \frac{\sqrt{3}}{-1} = -\sqrt{3} \] ### Step 9: Write the square roots Thus, the square roots of \(-2 + 2\sqrt{3}i\) are: \[ 1 + \sqrt{3}i \quad \text{and} \quad -1 - \sqrt{3}i \] ### Final Answer The square roots of \(-2 + 2\sqrt{3}i\) are: \[ \boxed{1 + \sqrt{3}i \quad \text{and} \quad -1 - \sqrt{3}i} \]
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