Question

How do you graph `y=-3cosx`?

Answer 1

graph{-3cosx [-10, 10, -5, 5]}

Explanation:

The graph of `y= cos x` is as follows:
graph{cosx [-10, 10, -5, 5]}

The graph of `y= 3cos x` is that graph scaled along OY with scale factor 3:
graph{3cosx [-10, 10, -5, 5]}

The graph of `y= -3cos x` is that graph inverted:
graph{-3cosx [-10, 10, -5, 5]}