if tan(1/2)x=2/5 and
if tan(1/2)x=2/5 and
证明1-tan^2x/1+tan^2x=cos^2x-sin^2x
函数f(x)=tan(x+1)+tan(x+2)+tan(x+3)+.+tan(x+2013)图像的一个对称中心为?
若tanx=1/2,tan(x-y)==-2/5,则tan(2x-y)
已知tan(x+y)=2/5,tan(x-y)=-1/4,则tan2x的值是
证明(1-2sin x cos x )/(cos^2x-sin^2x)=(1-tan x)/(1+tan x)
1)tan(x/2+π/4)+tan(x/2-π/4)=2tanx
if tan A=24/7 and 180°
2tan^2(x/2)+2=4tan(
tan^2x+1=sec^2x怎么记住
证(1/sin^2x)+(1/cos^2x)-(1/tan^2x)=2+tan^2x
求证 (1—tan^2X)/(1+tan^2X)=cos^2X—sin^2X