What is the limit of `(x^3+y^3)/(x^2+y^2)` as (x,y)-->(0,0)? I'm supposed to use polar coordinates to find the limit. The assignment says:...

The
problem requests to use parametric forms, hence, you need to convert the Cartesian coordinates
x,y into polar coordinates, thus, you need to substitute `r*cos t`  for x and `r*sin t`  for
y, such that: