I was reading a textbook and for the exercise part I faced this question that asked to figure if this integration is converge or divergent.
I tried to solve it with the limit comparison test and I couldn't find the proper function to compare with.
Can you tell me what do you think about this wanted function and how do you come up with that ?
I was wondering is it even a proper procedure to use limit comparison test?
$$\int_{0^+}^{+\infty}\frac{e^{-x}}{\sqrt{x}} dx$$
Best Answer
Hint:
Consider integrals over $[0,1]$ and $[1,\infty)$.
Try the limit comparison test with $e^{-x}$ as $ x \to \infty$ and $1/\sqrt{x}$ as $x \to 0$.