若COS(2/3π-2X)=-7/8,则SIN(X+π/3)=?A 1/4B 7/8C ±1/4D ±7/8求详细过程啊啊啊啊啊啊啊啊啊啊啊

若cos(π/3-2x)=-7/8则sin(x+π/3)等于 若函数f(x)=[2cos^3 x-sin^2 (x+π)-2cos (-x-π)+1]/[2+2cos^2(7π+x)+cos(-x)],（1）求证f(x)是偶函数若函数f(x)=[2cos^3 x-sin^2 (x+π)-2cos (-x-π)+1]/[2+2cos^2(7π+x)+cos(-x)],（1）求证f(x)是偶函数 （2）求f(π/3)的值 若x=π/12,则cos(2x-π)*cos[2(x-π)]=? 若F(sin x)=3-cos 2x 则F（cos x）=? 证明cos 2x cos x=1/2(cos x+cos 3x) 若2cos(3π-x)=cos(π/2+x),则sin(π+2x)= 若cosx=2/3,x是第四象限角,求sin(x-2π)+sin(-x-3π)cos(x-3π)/cos(π-x)-cos(-π-x)cos(x-4π)的值 cos^2 π/8+cos ^2 3π/8+ cos^2 5π/8+cos^2 7π/8=? 证明:函数f(x)=cos^2+cos^2(x+π/3)+cos^2(x-π/3)是常数函数 若X属于[-π/2,0],则函数f(x)=cos(x+π/6)-cos(x-π/6)+根号3倍的cosx的最小值是? cos（x-2派/3)=-cos(x+派/3) y=cos(π/3-x)cos[π/2（x-1)]判断奇偶性y=cos(π/3-x)cos(π/3+x)判断奇偶性 若sinx+sin^2x=1,则cos^2x+cos^4x=? 设f(sin x)=3-cos 2x,则f(cos x）=? 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- 若sin(π+x)+cos(π/2+x)=-m,则cos（3π/2-π）+2sin（6π-x）=? 若cos（3π-x）-3cos（x+π/2）=0,则tan（x+π/4）等于多少? cos(x-π/2)=3/5.则cos2x=