Answer: n(n + 1)/2.
- A n(n + 1)/2
- B n(n + 1) itself
- C n squared
- D simply 2n
Correct answer: A. n(n + 1)/2
Explanation: The sum of the first n natural numbers is n(n + 1)/2.
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.