Question

Identify the maximum and minimum values of the function y = 10 cos x in the interval [-2π, 2π]

Answer 1

Hello,

-1<=cos x <=1
==>-10<=10*cos x <=10
max y=10 if x=0 +2kπ ==>x=0,-2π,2π
min y=-10 if x=π+2kπ ==>x=-π,π