sin^2(兀/8)-cos^2(兀/8)

sin^2(兀/8)-cos^2(兀/8) 三角化简sin(x-5兀)cos[(-兀/2)-x]cos(8兀-x)/sin[x-(3兀/2)]sin(-x-4兀) 计算sin兀/8cos兀/8 2cos+7tan兀-4sin二分之3兀-8cos二分之兀等于 化简 cos(@-兀/2)/sin(5兀/2+@)*sin(@-2兀)*cos(2兀-@) 化简4sin派/8*cos派/8*(cos^2派/8-sin^2派/8) 若sinα+sin^2α=1,则cos^2α+cos^6α+cos^8α=? sin α+sin^2α=1,则cos^2 α+cos^6 α+cos^8α=多少?, cosα+cos^2α=1求sin^2a+sin^6a+sin^8a=? 已知cosθ+cosθ^2=1,则sinθ^2+sinθ^6+sinθ^8= 证明一个sin&cos的等式证明 1+sin^2(x)+sin^4(x)+sin^6(x)=[1-sin^8(x)]/[cos^2(x)] cosA+cos^2A=1,sin^2A+sin^4A+sin^8A 若sin(a-兀)=2cos(2兀-a)求sin(兀-a)+5cos(2兀-a)/3cos(兀-a)-sin(-a)的值 化简![sin(2兀—¤)cos(兀+¤)cos(兀/2+¤)] / [cos(兀-a)sin(3兀-¤)sin(-¤)] 2sin@+cos@等于? sinα+cosα=1,求cos^2α+cos^6α+cos^8α的值. 化简sin(α-5π)/cos(3π-α)×cos(π/2-α)/sin(α-3π)×cos(8π-α)/sin(-α-4π) Sin兀/2等于多少?cos兀/2等于多少