This question doesn't involve a specific problem, instead focuses on notation. With limits that approach infinity, is it incorrect to say that the limit approaches infinity from the positive/negative direction?
[Math] limit as x approaches infinity from the left (Notation)
infinitylimitsnotation
Best Answer
I'm assuming that you are talking about limits of real quantities (like in a usual calculus class). Then $\infty = +\infty$ can only be approached from the negative direction, and $-\infty$ only from the positive direction. So, for example, writing $x \to \infty^-$ would be redundant, and $x \to \infty^+$ wouldn't make sense.