JEE/Mathematics/Limits and Continuity

Calculus · Must Do

Limits and Continuity — JEE Main & Advanced Notes

Limits are local behaviour; continuity means value and limiting behaviour agree.

standard limitscontinuityLHL/RHLindeterminate forms
Copyright-safe content: These notes are rewritten from scratch. The uploaded PDFs were used only to understand chapter coverage, difficulty levels and test formats.

Concept Depth

Start Limits and Continuity by identifying definitions, standard forms, and the condition under which each formula is valid. JEE questions usually become hard when a familiar formula is used outside its comfort zone.

Solved-Example Method

For every example, write the trigger, the transformation, and the final shortcut. The goal is not to remember the solution, but to recognise why that method was chosen.

Advanced Trap Check

Before marking an answer, check domain, extraneous roots, sign changes, equality cases, and hidden constraints. These are the places where JEE Advanced turns a routine question into a rank-decider.

1. Introduction & Exam Weightage

Limits are local behaviour; continuity means value and limiting behaviour agree.

Material signal: Mapped from limits and continuity-differentiability revision assignments.

Priority: Must Do. Treat this as a moderate chapter inside the JEE Mathematics ladder.

2. Core Concepts & Definitions

  • Limit depends on nearby values, not necessarily the function value at the point.
  • Continuity requires LHL = RHL = f(a).
  • Indeterminate forms demand simplification or expansion.

3. Key Formulas with Derivation Hints

  • lim_{x o0} rac{sin x}{x}=1
    Hint: do not memorise this in isolation; connect it to the definition or diagram that produces it.
  • lim_{x o0} rac{e^x-1}{x}=1
    Hint: do not memorise this in isolation; connect it to the definition or diagram that produces it.
  • f(a)=lim_{x o a}f(x) for continuity
    Hint: do not memorise this in isolation; connect it to the definition or diagram that produces it.
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4. Solved Examples — Original Practice Models

Limits and Continuity: main-style warm-up

Problem: A direct one-step Limits and Continuity question is solved by identifying the governing definition before substituting values.

Method: write the target quantity, list the known values, use the standard relation, and check if the answer is dimensionally or logically possible. This prevents option-led guessing.

Limits and Continuity: advanced-style trap

Problem: A multi-condition Limits and Continuity problem often has an extra restriction hidden in domain, sign, interval or geometry.

Method: solve algebraically first, then filter using the domain/interval/geometry condition. In JEE Advanced, most wrong options come from skipping this final filtering step.

5. Common Mistakes & Traps

  • Substituting blindly into 0/0.
  • Checking only one side for piecewise functions.
  • Using degree comparison after cancellation is needed.

6. JEE Main Specific Strategy

For JEE Main, aim for fast recognition and clean substitution. Finish the first pass of Limits and Continuity questions in 60–90 seconds each. Prioritise standard formulas, short sign/domain checks and option elimination only after the setup is correct.

7. JEE Advanced Specific Strategy

For JEE Advanced, expect combined conditions, hidden domains, multi-correct traps and integer-style answers. Build the solution from definitions, not memorised tricks. When a parameter appears, solve the general case and then filter using restrictions.

8. Quick Revision Summary

  • Check LHL/RHL.
  • Use standard limits.
  • Simplify before substituting.
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Verified question bank

Limits and Continuity questions with answers

Open any of these 20 quality-checked JEE questions to review all four options, the correct answer, and the worked explanation.

  1. Question 1 · EasyBasic limits
  2. Question 2 · EasyStandard limits
  3. Question 3 · EasyStandard limits
  4. Question 4 · EasyContinuity definition
  5. Question 5 · EasyLeft and right limits
  6. Question 6 · EasyInfinite limits
  7. Question 7 · MediumFactoring
  8. Question 8 · MediumTrigonometric limits
  9. Question 9 · MediumTrigonometric limits
  10. Question 10 · MediumExponential limits
  11. Question 11 · MediumL'Hôpital
  12. Question 12 · MediumContinuity check
  13. Question 13 · MediumRemovable discontinuity
  14. Question 14 · HardJEE Main
  15. Question 15 · HardExponential limit
  16. Question 16 · HardJEE Advanced
  17. Question 17 · HardJEE Advanced
  18. Question 18 · EasyMixed
  19. Question 19 · MediumMixed
  20. Question 20 · HardMixed
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