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# When cosx=1, what does x equal?

Sep 30, 2016

$x$ can be any integer multiple of $2 \pi$, including $0$

#### Explanation:

The function $\cos \left(x\right)$ has period $2 \pi$ and $\cos \left(0\right) = 1$

Hence:

$\cos \left(2 n \pi\right) = 1 \text{ }$ for any integer $n$

graph{cos(x) [-10, 10, -5, 5]}