Sometimes we need to show that a claim is false. This can be done by finding a **counterexample**. Consider any claim of the form: . To show that the claim is false, we need to find a value of for which is true and is false.

That is, we need to prove the negation of the above claim: . Finding any that supports the negation of the original claim is sufficient to disprove it. Continue reading “Disproof by Counter Example”