化简:sin(4分之π-3x)cos(3分之π-3x)-sin(4分之π+3x)sin(3分之π-3x)

化简:sin(4分之π-3x)cos(3分之π-3x)-sin(4分之π+3x)sin(3分之π-3x) 化简[1-(sin^4x-sin^2cos^2x+cos^4x)/(sin^2)]+3sin^2x 已知sin(x-4分之3π)cos(x-4分之π)=-4分之1,则cos4x=? 已知sin(x-4分之3π)cos(x-4分之π)=-4分之1,则sin2x=? 已知sin（x-4分之π）等于3分之1,则cos（4分之π+x)等于? 化简sin(3π-x)cos(x-3/2)cos(4π-x)/tan(x-5π)cos(π/2+x)sin(x-5/2π) 化简sin(3π-x)cos(x-3/2)cos(4π-x)/tan(x-5π)cos(π/2+x)sin(x-5/2π) 化简2sin^2[(π/4)+x]+根号3（sin^x-cos^x）-1 由cos(a+b)=cos a cos b-sin a sin b cos(a-b)=cos a cos b+sin a sin b解题设a为锐角,证：1、2分之根3乘cos a + 2分之1乘sin a=cos(6分之π-a)2、cos a-sin a=根号2cos(4分之π+a) 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- cos（x-三分之派）=3/4,则sin（六分之派+x） 化简[1-(sin^4 x-sin^2 xcos^2 x+cos^4 x)]/(sin^2 x)+3sin^2 x 化简sin(x)(cos(x)+cos(3x)+cos(5x)+cos(7x)) 已知sin(x-y)cosx-cos(y-x)sinx=3分之5,y是第三象限角,求sin(y+5π分之4）的值 化简sin^4x+cos^4x-3/4 化简:sin^4 x+cos^4 x-3/4 化简sin（x+π/2）分之1+根号二cos（2x-π/4） f(x)=cos(2x-x/3)+2sin(x-π/4)sin(x+π/4)sin(x+π/4)化简.