Question

Proving $\sqrt{2}$ is an irrational number is an example of a/an.

• A. direct proof
• B. indirect proof
• C. postulate

Answer 1

The correct option is B indirect proof

For proving $\sqrt{2}$ is an irrational number, we first assume that $\sqrt{2}$ is a rational number. Further with logical explanation we understand that our assumption was wrong and hence it is proved that $\sqrt{2}$ is an irrational number.

This is an example of indirect proof as the consequent is first assumed to be false and later proved to be true.