This is a true/false question, and I have to say why it's true or false:
lim (x,y)-->(0,0) |x^2 - y^2| / (x^2 + y^2) = 1
just in case it's hard to interpret the question, it says that the limit as (x,y) approaches (0,0) of |x^2 - y^2| / (x^2 + y^2) is equal to 1.
I'm not allowed to use L'Hospital's rule to explain this.
Thanks in advance for your help.