求曲线sin(x+y)=xy+y^2在点(0,0)处的切线和法线方程.
问题描述：
求曲线sin(x+y)=xy+y^2在点(0,0)处的切线和法线方程.
答
cos(x+y)(1+dy/dx)=y+x*dy/dx+2y*dy/dx
x=0,y=0
1+dy/dx=0
dy/dx=-1
切线y=-x
法线y=x