# Homework Help: If cos(pi*n) = (-1)^n is cos(-pi*n) = (-1)^n

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1. Jul 24, 2017

### mrmerchant786

1. The problem statement, all variables and given/known data
i wassolving a Fourier series integral, and needed some help
if cos(pi*n) = (-1)^n is cos(-pi*n) = (-1)^n ?

2. Relevant equations
i think it is because cos is an even function so -x of the function should still remain the same, becuase if you look at the graph and flip it its still the same graph

if someone could reply to confirm my thoughts or tell me why its wrong, that would be great thanks :)

3. The attempt at a solution

2. Jul 24, 2017

### Buffu

you are correct because $\cos (x) = \cos (-x)$.

3. Jul 24, 2017

### mrmerchant786

thanks , thought so