Construct Proof using mathematical induction

Construct Proof using mathematical induction

Principles of Mathematical Induction

  • Mathematical induction is a method of proof often used to establish the truth of a statement for all natural numbers.
  • It involves two steps: the base case and the inductive step.
  • The base case shows that the statement holds for a specific initial example (usually, but not always, when the natural number is 1).
  • If for the inductive step, we assume that the statement holds for a certain number k (the inductive hypothesis) and prove that it holds for k + 1, the inductive step is complete.

Procedure for Inductive Proving

  • Identify the statement you are trying to prove and express it in a form suitable for induction (P(n)).
  • Begin the process by showing that the statement is true in the base case, usually when n=1 but can be any number depending on the problem (proving the base case).
  • For the inductive step, assume the statement is true for a certain natural number (P(k)).
  • Prove that the statement is then also true for the next number (P(k + 1)) - this involves logical deduction and algebraic manipulation derived from the assumption that P(k) is true.
  • If both steps are successful, it can be concluded that the statement is true for all positive integers onwards from the base case.

Common Pitfalls and Considerations

  • Always make the inductive hypothesis clear before attempting to prove the statement for k + 1.
  • Keep a keen eye for pattern recognition, this may involve re-arrangement, factoring, expanding and simplifying.
  • While working on your proof, make sure to justify each step of your argument.
  • Always explain your conclusion, recounting that the base case is true, the basis of your inductive assumption, and the outcome of the inductive step.
  • Be aware of statements that are false but might appear true in the first few instances; always confirm by checking multiple base cases if necessary.
  • False positives can sometimes occur, where the base case and inductive step seem to confirm the truth of the statement, but subsequent integers disprove it.

Benefits of Inductive Proofs

  • It allows us to prove infinitely many cases in one fell swoop.
  • It can give us insight into a problem, and allows us to make hypotheses about a general case from examining specific cases.
  • It can be used to establish the validity of formulas, patterns, and properties of numbers.

Through understanding these principles and methods, you should be well-equipped to tackle problems involving proofs by mathematical induction. Remember: proving maths using mathematical induction involves a logical sequence of assumptions and proofs, rather than the method of direct calculation or traditional problem-solving.