How do you use the amplitude and period to graph y=5+8cos2x?

Apr 22, 2016

This cosine wave has mean level along y = 5.

The period of y = b+a cos( kx + c) is $\frac{2 \pi}{k}$.
The amplitude is a and the mean level is y = b.

Here, b = 2, a = 8 and k = 2. So, the period is $\pi$.

The graph of one full wave is between $\left(- \frac{\pi}{4} , 5\right) \mathmr{and} \left(\frac{3 \pi}{4} , 5\right)$, bisected at $\left(\frac{\pi}{4} , 2\right)$.

The crest (zenith) is at (0. 13) and the lowest point (nadir) is at $\left(\frac{\pi}{.2} , - 3\right)$.. .