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# L'Hôpital's Rule

When you've got a limit that looks like 0/0 or ∞/∞, L'Hôpital's rule can often find its value -- and make it clear that not all infinities are equal!

# L'Hopital's Rule: Level 2 Challenges

Please help me! I kept using L'Hôpital's rule millions of times and I can't evaluate the limit below!

$\displaystyle \lim_{x \to 0} \frac {\cot x }{\csc x } = \ ?$

Details and assumptions:

• $$\frac{d}{dx}( \cot x ) = -\csc^2 x$$

• $$\frac{d}{dx}( \csc x ) = -\csc x \cot x$$

$\large \lim_{x \to 1}\frac {x^{n} + x^{n-1} + \ldots + x - n}{x - 1} = \ ?$

If the limit

$\lim _{ x\rightarrow 0 }{ \left( \frac { \sin { 2x } }{ { x }^{ 3 } } +a+\frac { b }{ { { x }^{ 2 } } } \right) } =0$

is true for constants $$a$$ and $$b$$, then what is the value of $$3a+b?$$

$\large{ \lim_{x \to 0}}\large \left(\frac{1}{x^4} - \frac{\displaystyle \int_{0}^{x^2} e^{-u^2} du}{x^6}\right) = \ ?$

What is the value of

$\lim _{ x \rightarrow 0 } \frac{ \tan x - x } { \sin x - x }?$

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