function limits

[rustic gale]

Theory of comparison?

[median edge]

Sorry I mean the comparison theorem

[keen atlas]

is this about series?

[heavy onyx]

L'Hôpital's rule allows you to figure out most of the usual indeterminate form, typically those requiring to compare polynomials, logarithms and exponentials

If you don't know L'Hôpital you can use more elementary tools though.

For example to prove log(x)/x tends to 0 when x goes to ∞, you can for example prove that log(x) ≤ √x

(you can prove this inequality by comparing log(x²) and x)