cos(9π/4)+tan(-7π/6)+sin(21π)=
cos(9π/4)+tan(-7π/6)+sin(21π)=
sin(-21π/4) cos(-20π/3) tan(-19π/6)=
SIN(-7/6π),cos(15/4π),tan(-8/3π),tan(33/4π)
求证:(1-sinα+cosα)/(1+sinα+cosα)=tan(π/4-α/2)
求证:1-2sinαcosα/cos²α-sin²α=tan(π/4-α)
已知tan(α+π/4)=3,求cosα+2sinα/cosα-sinα的值
试证明:1+2sinαcosα/cos平方α-sin平方α=tan(π/4-α)
已知tan(π-α)=2,求sinα-2sinαcosα-cosα/4cosα-3sinα的值
1.已知tan2分之α=2,求值:⑴ tan(α+4分之π);⑵ (6sinα+cosα)/(3sinα-2cosα)
已知tan(π-α)=2,求sin²α-2sinαcosα-cos²α/4cos²α-3s
若tanα=m,求sin(-6π-α)cos(4π+α)的值
已知tan(3π+α)=2,求:1、(sinα+cosα)²;2、sinα-cosα/2sinα+cosα