(2sinx*cosx)/sin^2x+cos^2x=(2tanx)/tan^2x+1 怎么推导的?

(sin^x/sinx-cosx)-sinx+cosx/tan^2x-1 求证 sin^2x/(sinx-cosx)-(sinx+cosx)/tan^2 x-1=sinx+cosx sinx+cosx/sinx-cosx=2 求sinx/cos^3x +cosx/sin^3x 证明:sin2x=2sinx*cosx为什么sin(x+x)=sinx*cosx+cosx*sinx? cosx-sinx/1+sin^2x不定积分 ∫sinx/(cosx-sin^2x)dx 求证sin^2x/sinx-cosx-(sinx+cosx)/(tan^2-1)=sinx+cosx谢谢GGJJ 化简[sin^2(x)]/(sinx-cosx)-(sinx+cosx)/[tan^2(x)-1]-sinx 利用cosx=sin(π/2-x),sin'x=cosx,证明(cosx)'=-sinx 3sinx-2cosx=0 (1)(cosx-sinx)/(cosx+sinx)+(cosx+sinx)/(cosx-sinx) (2)sin^2 x-2sinxcosx+4cos^2 x (1+Sinx+Cosx+SinxCosx)/(Sinx+Sin^2 x)怎么化简成(Cscx+1+Cotx+Cosx)/(1+Sinx)? 证明(1+secx+tanx)/(1+secx-tanx)=(1+sinx)/cosx左边=（cosx/cosx+1/cosx+sinx/cosx)/（cosx/cosx+1/cosx-sinx/cosx)=(cosx+1+sinx)/(cosx+1-sinx)=(cosx+1+sinx)^2/[(cosx+1+sinx)(cosx+1-sinx)]=(cos²x+sin²x+2*sinx*cosx+2*cosx+2*sinx+1)/(cos² 化简sin^4x/sinx-cosx - (sinx+cosx)cos^2x/tan^2x-1 已知sinx=2/3,求(cosx-sinx/cosx+sin)+(cosx+sin/cosx-sinx)的值. 化简(sin^2x/sinx-cosx) -(sinx +cosx/tan^2x-1) 化简：sin^2`x/(sinx-cosx)- (sinx+cosx)/tan^2`x - 1. 2sina(x-π/4)sin(x+π/4) 怎么转换成(sinx-cosx)(sinx+cosx)? 已知sinx+cosx/sinx-cosx=3,求tanx,2sin^2x+(sinx-cosx)^2的值