化简cos²(π/4-α)+cos²(π/4+α)=
问题描述:
化简cos²(π/4-α)+cos²(π/4+α)=
答
1
cos(pi/4 - a) = sin(pi/2 - (pi/4 + a)) = sin(pi/4 + a)
所以,原式=sin(pi/4 + a)^2+cos(pi/4 + a)^2=1
pi是圆周率