If f(x)=cos(x)f(x) = \cos(x)f(x)=cos(x) restricted to [0,π][0, \pi][0,π], what is the range?
[0,1][0, 1][0,1]
[−1,1][-1, 1][−1,1]
[−1,0][-1, 0][−1,0]