如果sin(π/2+α)=cosα,sin (π/2-α)=cosα,那么sin(π/2+α)=sin(π/2-α)对吗
已知(3sinα+cosα)/(3cosα-sinα)=2,则2-3sin(α-3π)sin(1.5π-α)-[cos(
sin(π/2+α)=cosα,那如果sin(-π/2+α)=-cosα
2sin²α-sinαcosα-3cos²α=0,α∈(0,π/2),那么sinα=多少?
若(sinα+cosα)/(sinα-cosα)=2 则sin(α-5π)·sin(3π/2-α)=?
若sinα+cosαsinα−cosα=2,则sin(α-5π)•sin(3π2-α)等于( )
α属于(0,π/2)且2sin²α-sinαcosα-3cos²α=0求sin(α+π/4)/sin
sin(π/2+α)·cos(π/2-α)/cos(π+α)+sin(π-α)·cos(π/2+α)/sin(π+α)=
已知cos(π/2+α)=sin(α-π/2) 求sin(π-α)-cos(π+α)/cos(5π/2 -α)+2sin
已知3sinα-2cosα=0,求(cosα-sinα)/(cosα+sinα)+(cosα+sinα)/(cosα-s
已知α∈(π,2π) sinα+cosα=1/5 求sinα*cosα sinα-cosα
已知tan(3π+α)=2,求:1、(sinα+cosα)²;2、sinα-cosα/2sinα+cosα
已知tan(π-α)=2,求sinα-2sinαcosα-cosα/4cosα-3sinα的值