Recent content by adron

x^2 + y^2 = 1 doesn't it? so then (r cos(theta))^2 + (r sin(theta))^2 = 1 = x^2 + y^2 And then I just rearranged them to find r in terms of x,y.

Ok, so now I have r = (x^2 + y^2)/sqrt(cos^2 theta + sin^2 theta) since x^2 + y^2 = 1. Is that correct? And is that the same as r(x,y)?

Homework Statement Say z = f(x,y) where x = r cos(theta) and y = r sin(theta), how would I go about rearranging this to find r(x,y)? Homework Equations The Attempt at a Solution I thought maybe I should find r in terms of x and y and then equate them, but I don't think that's...

Sorry it's been a while since I did anything to do with polar, how do I do that?

Homework Statement Find the limit of ((x^3 + (4x^2)y)/(x^2+2y^2)) as (x,y) -> (0,0) Homework Equations The Attempt at a Solution I am guessing the limit is equal to 0, and I know I have to use 0 < sqrt(x^2 + y^2) < delta where |f(x,y) - L| < epsilon I just have no idea what to do next I...