化简1/sin^2x+1/cos^2x

化简 1/2cos x-根号3/2sin x 根3sin x+cos x 化简[1-(sin^4x-sin^2cos^2x+cos^4x)/(sin^2)]+3sin^2x 2cos x (sin x -cos x)+1 化简（1)√3sin x+cos x (2）√2(sin x-cos x) （3）√2cos x-√6sin x 化简f(x)=2cos(x/2)·(sin(x/2)+cos(x/2))-1 化简1—-cos(2X)+sin(2X) 化简：1+sin（x-360度）cos（x-270度）-2cos平方x 化简2sin^2[(π/4)+x]+根号3（sin^x-cos^x）-1 求证（cos^2 x-sin^2 x)(cos^4 x+sin^4 x)+1/4 sin 2x sin 4x=cos 2 lim(sin(x^2*cos(1/x)))/x怎么做? 证明(1-2sin x cos x )/(cos^2x-sin^2x)=(1-tan x)/(1+tan x) (1-(sin^4x-sin^2xcos^2x+cos^4x)/sin^2x +3sin^2x