若cos(x-40°)=cos(x+20°)+cos(x-20°),则tanx的值______.
[tanx+(1/tanx)]cos^x
tanx/(cos^2)x dx
已知sin(x+20)=cos(x+10)+cox(x-10).求tanx的值
(tanX+cotX)cos²X=?
(tanx+1/tanx)cos^2 x等于
cos(x+y)=1/5,cos(x-y)=3/5则tanx.tany=?
已知tanx=-2,则sin^2*x+3cos^2*x/3sin^2*x -cos^2*x 的值为?
若tanx/tanx-1=-1,求sin(π/2+x)cos(3π-x)的值
函数y=3sin(x+20°)+5cos(x-10°)的最大值是______.
已知tanx=根号3,则sin2x/1+cos^x
已知tanx=2,则sin2x/(1+cos^x)
若f(cos x)=cos 2x,则f(sin 15度)的值?