Limit laws
The rules for evaluating limits of sums, products, quotients and compositions.
Limit laws
\lim_{x \to a}\,[f(x) + g(x)] = \lim_{x \to a} f(x) + \lim_{x \to a} g(x)
The limit laws let you split a limit into smaller limits. Every law with its conditions, worked examples and the mistakes that break them.
Direct substitution
\lim_{x \to a} f(x) = f(a)
Direct substitution evaluates a limit by plugging in the value. Learn when it works, how to read the result and what to do with 0/0 or a/0.
L'Hôpital's rule
\lim_{x \to a} \frac{f(x)}{g(x)} = \lim_{x \to a} \frac{f'(x)}{g'(x)}
L'Hôpital's rule evaluates 0/0 and ∞/∞ limits by differentiating the top and bottom. The exact conditions, worked examples and other indeterminate forms.
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