已知sin2x=1⼀3,则cos^2(x-π⼀4)=

2025-06-27 03:08:09
推荐回答(1个)
回答1:

(cos(x-π/4))^2
= (1/2)[1+ cos(2x-π/2)]
= (1/2)[1+ cos(π/2-2x)]
= (1/2)(1+ sin2x)
= (1/2)(1+ 1/3)
=2/3