e^xy+tan(x+y)=2,求dy
问题描述：
e^xy+tan(x+y)=2,求dy
答
e^xy+tan(x+y)=2e^xy(y+xdy/dx)+1/cos^2(x+y) * (1+dy/dx)=0ye^xy+xe^xy *dy/dx +1/cos^2(x+y) +dy/dx *(1/cos^2(x+y))=0ye^xy+1/cos^2(x+y)=-(xe^xy+1/cos^2(x+y))dy/dxdy=-[ye^xy+1/cos^2(x+y)]/(xe^xy+1/cos^2(x+...