Factorization vs Rationalization vs L'Hopital
Factorization is best for polynomial 0/0 forms. It's fast and algebraically clean. Example: at x=2 factors immediately.
Rationalization is best for expressions involving surds (square roots). Multiply by the conjugate to eliminate the radical. Example: (sqrt(1+x)-1)/x — multiply by (sqrt(1+x)+1).
L'Hopital's Rule is the universal method but often the slowest. It works for any 0/0 or infinity/infinity form but may require multiple applications.
Standard Limits vs Taylor Expansion
Standard limits are one-step solutions for simple expressions. Use them when you can directly match the pattern , (e^(f(x))-1)/f(x), etc.).
Taylor expansion is more powerful for complex combinations. It handles expressions like ^5 in one step where L'Hopital would need five applications.
When to Use Which:
- Polynomial ratio: Factorization first
- Surd present: Rationalization
- Single trig/exponential function: Standard limits
- Multiple functions combined: Taylor expansion
- Nothing else works: L'Hopital's Rule
- Oscillatory function times vanishing: Sandwich Theorem
- Base -> 1, exponent -> infinity: 1^infinity formula
- Root existence: Intermediate Value Theorem