(x^3+sin^2x)cos^2x 在-π/2到π/2的积分

已知sin(x)+3cos(x)=2,求sin(x)-cos(x)/sin(x)+cos(x)=? sin[cos^2(x^3+x)],求导 2sin^2x - 5sin x cos x=3 cos^2x,求X, 化简y=sin^2(x)+2sin(x)cos(x)+3cos^2(x) 化简 1/2cos x-根号3/2sin x 根3sin x+cos x 证明sin^2(x)+cos^2(x+30)+sin(x)cos(x+30)=3/4 sin^3 x -cos^3 x sin^3 x -cos^3 x =(sin x -cos x )(sin^2 x +sin x*cos x +cos^2 x )问下这个是个公式还是什么?怎么样算出来的? 化简[1-(sin^4x-sin^2cos^2x+cos^4x)/(sin^2)]+3sin^2x 已知tan=2,求(cos x+sin x)/(cos x-sin x)+sin^2x 化简(sin x+cos x-1)(sin x-cos x+1)/sin 2x (1-(sin^4x-sin^2xcos^2x+cos^4x)/sin^2x +3sin^2x 化简[1-(sin^4 x-sin^2 xcos^2 x+cos^4 x)]/(sin^2 x)+3sin^2 x 2(sin^6x+cos^6)-3(sin^4x+cos^4x) 化简sin(x+7π/4)+cos(x-3π/4）步骤我已经找到撒sin(x+7π/4)+cos(x-3π/4)=sin(x+2π-π/4)+cos(x-π+π/4)我问下这一步是在干嘛?=sin(x-π/4)+cos[-(π-x-π/4)]=sin(x-π/4)+cos(π-x-π/4)=sin(x-π/4)-cos(x+π/4)=sin(x-π/4)-cos(x+π/2- 2cos x (sin x -cos x)+1 y=2cos x (sin x+cos x) 化简sin(x)cos(x)cos(2x) 化简sin(x)cos(x)cos(2x)