cos^2 5π/12-sin^2 7π/12=? 求详细过程
cos(5π-a)+sin(2π-a)分之cos(-a)-sin(3π-a)=()要答案和计算过程,过程要详细
已知tan=4,求sinα+4sinαcosα-2cos²α的值.详细过程
已知sinα=2sinβ,tanα=3tanβ求cosα【求详细过程,谢谢]
sin²α+√3sinαcosα-2cos²α=0,α∈(π/6,5π/12),求:(1)sin(2
已知α是锐角,tanα=1/2,求(sinα-2cosα)/2cosα+sinα的值(详细过程)
cos(π/2+α)=-sinα转换过程
已知cos2X=根号2/3,则sin^4X+cos^4的值为?求详细过程!
①化简[sin(2π+α)*cos(7π-α)]/cos(-α)②已知cosθ=-3/5,θ∈(π/2,π),求sin(
已知cos(π/2+a)=2sin(a-π/2)求sin(π-a)+cos(a+π)/5cos(5π/2-a)+3sin
已知cos(π/2+α)=sin(α-π/2) 求sin(π-α)-cos(π+α)/cos(5π/2 -α)+2sin
a为锐角 cos(a+π/6)=4/5 求sin(2a+π/12)
已知 sinα+2cos(5π/2+α)/cos(π-α)-sin(π/2-α)=-1/4 求(sinα+cosα)平方