求方程y'+siny+x*cosy+x=0的同届

求方程y'+siny+x*cosy+x=0的同届 求微分方程y'=(x+1-siny)/cosy的通解 sin(x+y)cosy-cos(x+y)siny求解释 已知cos(x+y)cosy+sin(x+y)siny=4/5,求tanx的值 为什么sinx*cosy-cosx*siny=sin(x-y) 证明.（sinx+siny)/cosx-cosy=ctg(y-x)/2 已知cosx+cosy=1/2,sinx-siny=1/3,求cos(x+y) cosx-cosy=4/1,sinx-siny=3/1求cos(x-y) sinx+siny=2/5,cosx+cosy=6/5,求cos(2x-2y) 已知sinx+siny=0.4,cosx+cosy=1.2,求cos(x-y) sinx+siny=-1/3 cosx+cosy=1/2,求sin(x+y)的值. sinx+siny=1/4,cosx+cosy=1/3求tan(x-y) sinx+siny+sinz=0;cosx+cosy+cosz=0;求cos(x-y) 求由方程x-y+1/2siny=0所确认的隐函数的二阶导数y'=2/(2-cosy)到了二阶求导就不明白了(y')'=(2/(2-cosy))' 然后我算出了y''=(2-cosy-2siny)/(2-cosy)^2 我高数方面很差,求详解下. 已知sinx+siny=1/3,cosx-cosy=1/5,求cos(x+y),sin(x-y).求过程! 已知sinx-siny=1/2,cosx-cosy=1/2,x、y均为锐角,求sin(x-y) sinx+siny=√2/2 cosx+cosy=√6/2 求sin(x+y)求解答. sinx+siny=√2/2 cosx+cosy=√6/2 求sin(x+y)求解答