Question

What is the domain and range of `y= 4 cos x`?

Answer 1

Domain: `x in RR`
Range: `-4geyge4`

Explanation:

The domain is the list of all allowable `x` values - that is to say - it results in `y` values that are defined.

With the function `cos`, it's a sinusoidal graph that cycles around the `x`-axis:

graph{4cosx}

and so the domain is all reals, or `x in RR`

The range is the list of all the values generated from the domain.

In this case, the resulting `y` values cycle between 4 and `-4`, and so the range is `-4geyge4`