SOLUTION: Prove (1+i)^n+(1-i)^n=2^(n/2+1)cos (n3.14/4)

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Question 1024255: Prove (1+i)^n+(1-i)^n=2^(n/2+1)cos (n3.14/4)
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
de Moivre's formula.
Similarly,
, since cosine is an even function and sine is an odd function.
Hence,