Hi I have problem to decide if
is continuous at (0,0).
I have tried to slove this by polar cordinates
but from here the only thing I can tell is , that for every teta, the limit will be 0.
Is it Enough? because it seems to me that in this case I am only showing that for every linear path to (0,0) the limit will be 0 ? and is this function really continuous?
one more thing I heard about a Rule of thumb that if the sum of the powers in the numerator is lower then the denominator the limit doesn't exist. is it allways true? thanks,