When taking the right or left hand limit, if direct substitution results in (non zero #)/zero, my prof today asked the question: "'generally speaking', how would we know if it is + infinity or -infinity?"
If this "generally speaking" refers to method of determining the +/- of infinity, what are some methods that are not applicable in determining the direction of the infinite asymptote?
Is there a situation where methods such as plugging in numbers close to x (for example 3.0000001 for lim f(x) --> 3+ when f(x)'s denominator is x - 3 or 3 - x (in its simplest form)) will not be helpful in determining the +/- of the asymptote?
Thanks for help!!:)