Question

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

Answer 1

This cosine wave has mean level along y = 5.

The period of y = b+a cos( kx + c) is `(2pi)/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 `(-pi/4, 5) and ((3 pi)/4, 5)`, bisected at `(pi/4, 2)`.

The crest (zenith) is at (0. 13) and the lowest point (nadir) is at `(pi/.2, -3)`.. .