(cosx)^y=(siny)^x直接两边对x求导怎么算,不要先取自然对数的方法

求证：tan(x+y)+tan(x-y)=sin2x/cosx*cosx-siny*siny 证明sinx+cos(x+y)siny/cosx-sin(x+y)siny=tan(x+y) (cosx)^y=(siny)^x直接两边对x求导怎么算,不要先取自然对数的方法 (cosx)^y=(siny)^x对X求导? 为什么sinx*cosy-cosx*siny=sin(x-y) 证明.（sinx+siny)/cosx-cosy=ctg(y-x)/2 证明cosx-cos(x+2y)/2siny= sin(x+y)证明cosX-cos(x+2y)/2siny= sin(x+y) 证明cosx(cosx-cosy)+sinx(sinx-siny)=2sin(x-y)/2 若cos(x+y)cosy+sin(x+y)siny=0,则cosx= cos(x+y)*cos(x-y)=cos*cosx+sin*siny 设z=x^2siny-y^2cosx 求偏z/偏X cosx+cosy=1/2,sinx-siny=1/3,则cos(x+y)=? cosx-cosy=1/2,sinx-siny=1/3,sin(x+y)=RT 已知cosx+cosy=1/2,sinx-siny=1/3,则cos(x+y)= sinx-siny=1/3,cosx-cosy=2/3,sin(x+y)=? sinx+cosy=1/3 cosx+siny=1/6 则sin(x+y)=?RT 不定积分通解cosx siny dy=cosy sinx dx,y(x=0)=pi/4 若cosx*cosy+sinx*siny=1/3 ,则cos(2x-2y)=?