If n is a positive integer,then (1 + i)^n + ( | vedclass

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(C) We express $1+i$ and $1-i$ in polar form: $1+i = \sqrt{2} \left( \cos \frac{\pi}{4} + i \sin \frac{\pi}{4} \right)$ $1-i = \sqrt{2} \left( \cos \f

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$(\sqrt{2})^{n+2} \cos \left( \frac{n\pi}{4} \right)$

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(C) We express $1+i$ and $1-i$ in polar form: $1+i = \sqrt{2} \left( \cos \frac{\pi}{4} + i \sin \frac{\pi}{4} \right)$ $1-i = \sqrt{2} \left( \cos \frac{\pi}{4} - i \sin \frac{\pi}{4} \right)$ Using De Moivre's theorem: $(1+i)^n + (1-i)^n = (\sqrt{2})^n \left( \cos \frac{n\pi}{4} + i \sin \frac{n\pi}{4} \right) + (\sqrt{2})^n \left( \cos \frac{n\pi}{4} - i \sin \frac{n\pi}{4} \right)$ $= 2 \cdot (\sqrt{2})^n \cos \frac{n\pi}{4}$ $= 2^1 \cdot 2^{n/2} \cos \frac{n\pi}{4}$ $= 2^{(n/2) + 1} \cos \frac{n\pi}{4}$ $= (\sqrt{2})^{n+2} \cos \frac{n\pi}{4}$

If $n$ is a positive integer,then $(1 + i)^n + (1 - i)^n$ is equal to

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