极限limxy/(x+y)=?x→0,y→0,lim(xy)/(x+y)=?

Question

极限limxy/(x+y)=?
x→0,y→0,lim(xy)/(x+y)=?

Answer 1

x=t,y=-t+t^3
lim xy/(x+y) t→0
=lim(t^4-t^2)/t^3=lim t-1/t)
不存在