化简2cos^4x-2cos^2x+1/2
cos x>-1/2
2cos x (sin x -cos x)+1
cos(x^2)dx
2(cos x)^2=1+cos 2x,
∫ (1+cos^2 x)/cos^2 x dx =
Cos x=-1/2
化简f(x)=2cos(x/2)·(sin(x/2)+cos(x/2))-1
化简 1/2cos x-根号3/2sin x 根3sin x+cos x
化简2cos^4x-2cos^2x+1/2
化简[1-(sin^4x-sin^2cos^2x+cos^4x)/(sin^2)]+3sin^2x
化简2*(sinxcosx-cos平方x)+1
化简:1+sin(x-360度)cos(x-270度)-2cos平方x