Consider the graph of the cosine function shown below. y=4 cos (2 x)

Question

a. Find the period and amplitude of the cosine function.
b. At what values of θ for 0 ≤ θ ≤ 2π do the maximum value(s), minimum value(s), and zeros occur?
so i don't know how to show the graph on here but
i find the period which was π
and the amp was 4
but for the min i found x=0+ 2π * c
and the max x = π/2 + 2π * c but i cant find the zero values any tips to figure out please?

Answer 1

try using the unit circle as a guide

Answer 2

thankyou