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Question 61

Let $$\alpha$$ and $$\beta$$ be the roots of the equation $$x^2 + (2i - 1) = 0$$. Then, the value of $$|\alpha^8 + \beta^8|$$ is equal to

The equation is $$x^2 + (2i - 1) = 0$$, which gives $$x^2 = 1 - 2i$$.

Let $$\alpha$$ and $$\beta$$ be the roots. Since the equation is $$x^2 = 1 - 2i$$, we have $$\alpha = -\beta$$, so $$\alpha^2 = \beta^2 = 1 - 2i$$.

Now compute the powers:

$$\alpha^8 = (\alpha^2)^4 = (1 - 2i)^4$$

$$\beta^8 = (\beta^2)^4 = (1 - 2i)^4$$

Therefore $$\alpha^8 + \beta^8 = 2(1 - 2i)^4$$.

Compute $$(1 - 2i)^2 = 1 - 4i + 4i^2 = 1 - 4i - 4 = -3 - 4i$$.

Compute $$(1 - 2i)^4 = (-3 - 4i)^2 = 9 + 24i + 16i^2 = 9 + 24i - 16 = -7 + 24i$$.

So $$\alpha^8 + \beta^8 = 2(-7 + 24i) = -14 + 48i$$.

$$|\alpha^8 + \beta^8| = |-14 + 48i| = \sqrt{196 + 2304} = \sqrt{2500} = 50$$

The answer is Option A: 50.

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