yˊ=1/xy*[sin(xy^2)]^2-y/2x答案是设u=xy^2 ,最后结果是uˊ=2/(sinu)^2

yˊ=1/xy*[sin(xy^2)]^2-y/2x答案是设u=xy^2 ,最后结果是uˊ=2/(sinu)^2 Xy-sin(x+y)=1 求Y的导数 xy-sin(πy^2)=0 求dy/dx xy-sin(πy^2)=0隐函数求导 已知y=sin(xy),求其导数. sin(xy)=x+y,求dy sin(xy)=x 求dx/dysec(xy)-y ]/x 还是 x/[sec(xy)-y] 已知x+y=1,xy=-2,则x²y+xy²-2xy 1-2/x+y=xy,4y+6x=xy.求xy的解? xy^2-e^x+e^y=1 求y' 是xy^2 不是xy ( )-(x^2+3xy)=-xy-1/3y^2 xy'+y=-xy^2的通解 Z=x*sin xy+e^x+y或设y=(x)是由方程xy+sin x+sin y=1确定,求y” 当x=3,y=3分之1时,求代数出3xy-[2xy-2(xy-2分之3xy)+xy]+3xy的值 sin(x +y^2) +3xy=1求微分求详解! sin y+e^z-xy^2-1=0所确定的隐函数,求dzrt 求xy-sin(πy^2)=0在（0,-1）的二阶导数. 已知1/x-1/y=2,求3x+7xy-3y/2x-3xy-2y答案是1/x-1/y=2(y-x)/xy=2 得：x-y=-2xy(3x+7xy-3y)/(2x-3xy-2y)=[3(x-y)+7xy]/[2(x-y)-3xy]=(-6xy+7xy)/(-4xy-3xy)=xy/(-7xy)=-1/7 谁能帮我解释一下=[3(x-y)+7xy]/[2(x-y)-3xy]=(-6xy+7xy)/(-4xy-3xy) 是怎