JEE Main Limits and Continuity 2027 — Key Concepts and Formulas
Limits and Continuity forms the foundation of Calculus in JEE Mathematics. Master the standard limits, L’Hôpital’s Rule, and continuity conditions to score well in this predictable chapter.
Standard Limits — Must Memorize
| Limit | Value |
|---|---|
| lim(x→0) (sin x)/x | 1 |
| lim(x→0) (tan x)/x | 1 |
| lim(x→0) (e^x – 1)/x | 1 |
| lim(x→0) (a^x – 1)/x | ln a |
| lim(x→∞) (1 + 1/x)^x | e |
| lim(x→0) (ln(1+x))/x | 1 |
Continuity — Three Conditions
A function f(x) is continuous at x = a if and only if:
- f(a) is defined (exists)
- lim(x→a) f(x) exists (LHL = RHL)
- lim(x→a) f(x) = f(a)
L’Hôpital’s Rule — When to Apply
Apply L’Hôpital’s Rule only for 0/0 or ∞/∞ indeterminate forms: differentiate numerator and denominator separately (not as a quotient), then take the limit again. Common mistakes: applying it for non-indeterminate forms, or forgetting to re-check if another application is needed.
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