Question

a. Find the period and amplitude of the cosine function.
b. At what values of theta for 0<=theta<=pi/2 do the maximum values, minimum values, and zeros occur?

Answer 1

the period is easy to see with your eyes
the hard part is figuring out what the units are on the \(x\) axis

Answer 2

the whole thing from left at \(0\) to the right at \(2\pi\) is 4 periods
two periods is half of that from \(0\) to \(\pi\)
and one period is half of thatfrom \(0\) to \(\frac{\pi}{2}\)

Answer 3

here is another picture of the same function
http://www.wolframalpha.com/input/?i=2cos%284x%29++domain+0..2pi

Answer 4

wait so that's the answer??