Question

How do you find cos 8(pi) by referring to the graph of the sine or cosine function?

Answer 1

`cos(8pi)=1`

Explanation:

Since `8pi` is a multiple of the period of cosine function, you can write that:

`cos(8pi)=cos(0)`.

Now if we look at the graph of cosine function we see., that `cos(0)=1`. So finally we can write, that:

`cos(8pi)=cos(0)=1`