题目

计算cos^4(π/8)+sin^4(π/8)=____ 怎么做的?

提问时间：2020-10-13

答案

cos^4(π/8)+sin^4(π/8)
=(cos^2(π/8)+sin^2(π/8))^2-2cos^2(π/8)sin^2(π/8)
=1-0.5sin^2(π/4)
=3/4