# Limits – Key Rules

## Standard Limits
lim (x → 0) sin x / x = 1  
lim (x → 0) (1 − cos x) / x² = 1/2

## Techniques
- Factorization
- Rationalization
- Standard identities

## Infinite Limits
If f(x) → ∞ as x → a, limit diverges

## Common Mistakes
- Cancelling terms incorrectly
- Ignoring domain restrictions