Question

How do you find the range of `y = -2 cos 3x`?

Answer 1

Range of `y=-2cos3x` is `[-2,+2]`

Explanation:

Range of `cos(theta)` for any Real `theta` (including `3x`) is [-1,+1]

Multiplying this by `(-2)` just stretches the range to `[2,-2]`