# How do you graph y=2cos3x?

Sep 19, 2015

Graph it to see what it looks like.

#### Explanation:

For a cosine function of the form $y = A \cos \left(B x\right)$, $A$ is the amplitude (maximum absolute value), and $B$ is the number of cycles completed every $2 \pi$ interval (or one cycle every $\frac{2 \pi}{B}$ interval).

For this function, the amplitude is $2$, giving the oscillation between $- 2$ and $2$, and the cycle period is $\frac{2 \pi}{3} \approx 2.09$.

The graph looks like this:

graph{2cos(3x) [-4, 4, -2.5, 2.5]}