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📐 Mathematics  ·  Principle of Mathematical Induction  ·  JEE

What is the first step of a proof by mathematical induction?

Answer: Verify the base case, usually P(1).

  • A Assume P(k) is true before checking anything else
  • B Verify the base case, usually P(1)
  • C Prove P(k+1) directly without a base case
  • D Substitute n equal to infinity into the statement

Correct answer: B. Verify the base case, usually P(1)

Explanation: The first step (base case) checks that the statement is true for the smallest value of n, usually n = 1.

Induction as a Domino ChainP(1): base case fallsP(k) knocks down P(k+1)...and so on, foreverBase case = first domino tipped; inductive step = each domino guaranteed to tip the next one

Mathematical induction works like a row of dominoes: proving the base case P(1) tips the first domino, and proving the inductive step (P(k) ⟹ P(k+1)) guarantees each domino knocks over the next - together these two facts guarantee ALL dominoes fall, without checking each one individually.

Concept context

A proof technique used to establish that a statement is true for every natural number, using a base case and an inductive step.

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