已知tanx 2 则sin^2x-sinxcosx
已知sin(x-45°)=四分之根号2,求sinxcosx,tanx+1/tanx
已知tanX=2求2sin^2X+sinXcosX-3cos^2X
已知tanx=-0.5,求sin^2x+2sinxcosx-3cos^2x的值,
已知(1+tanx)/(1-tanx)=3+根号二,求cos²x+sinxcosx+2sin²x的值
已知tanx=-4,求sin^2 x及sinxcosx的值.
已知sin(x-45°)=√2/4.求(1)sinxcosx值,(2)求tanx+(1/tanx)值
求证(1-2sinxcosx)/(cos^2x-sin^2x)=(1-tanx)/(1+tanx)
求证1+2sinxcosx/cos^2x-sin^2x=1+tanx/1-tanx
证明:(1+2sinXcosX)/(sin^2X-cos^2X)=(tanX+1)/(tanX-1)
(cos^2x-sin^2x)/(1-2sinxcosx)=(1+tanx)/(1-tanx)
1).证明1-2sinxcosx/cos²x-sin²x=1-tanx/1+tanx
sin^2xtanx+cos^2x/tanx+2sinxcosx-(1+cosx/sinxcosx)化简