Question

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

Answer 1

Range [-2,2]

Cosine value varies from -1 to 1, hence -2cos 3x can vary from +2 to -2. The range of the given function , in interval notation, would thus be [-2,2]. In set builder notation it can be expressed as `{ yinR |-2<=y<=2` }