函数y=cos(x-π/4)cos(x+π/4)的值域是?
问题描述:
函数y=cos(x-π/4)cos(x+π/4)的值域是?
答
y=cos(x-π/4)cos(x+π/4)
=sin(x+π/4)cos(x+π/4)
=sin(2x+π/2)/2
所以其值域为[-1/2,1/2]