Question

How do you draw the graph of `y=-cosx` for `0<=x<2pi`?

Answer 1

Answer below...

Explanation:

I am first assuming you understand the graph of `y = cosx` pretty well:

`color(blue)(y = cosx`

graph{cosx [-0.4, 6.5, -2.5, 2.5]}

Now we must use our knowledge of tranformation, if `y= f(x)` then `y = -f(x)` represents `y = f(x)` reflected in the `y` axis, or in other words turning any posotive values of `y`, into negative, etc...

So hence just flip horozontally:

`color(green)(y = -cosx` graph{-cosx [-0.4, 6.5, -2.5, 2.5]}