Question

How to plot the graph of `f(x)=cos 8(pi)`?

Answer 1

The line `y = 1`.

Explanation:

First of all, note that there is no dependence of the function on `x`. Thus it is a constant function. We need to find the value of the function.

We know that the period of `cos` is `2pi`. Thus we write:
`cos(8pi) = cos(0 + 4 . 2pi) = cos(0) = 1`

Thus the graph of the function is `y = 1`, a line parallel to the x-axis having y-intercept of 1.