Question

How do you graph `y=2cos2x`?

Answer 1

You can deduce a lot of things from the equation representing your function.

It is a cosine with amplitude of `2` and a length `lambda` (before it repeats itself) that can be found using the `2` in front of `x` as the value of `k` in:

`k=(2pi)/lambda`

giving: `lambda=pi` basically it is a squashed cosine function that instead of going from `0` to `2pi` goes from `0` to `pi`: