lim of(adsbygoogle = window.adsbygoogle || []).push({});

cos((x^2 + y^2) - 1)/(x^2 + y^2)

as (x,y) approaches (0,0)

I have no clue how to tackle this problem. I tried to find the level set so at least I can have a clue of what the graph looks like, but then, I didn't know how to find the level sets either. If I set c = the equation, I have 2 unknowns so I cannot solve, and its not an obvious graph like a circle or something. On the other hand, I tried l'hopitale but that needs the derivative and what in the world am i taking a derivative in terms of since there are 2 variables?

I'm very confused. PLEASE HELP!

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Multivariable Calculus Limits

**Physics Forums | Science Articles, Homework Help, Discussion**