Proof by contradiction

What you'll learn

1. 1

   Imagine you're a detective 🕵️. To prove something is true, you first pretend it's FALSE and see if that leads to nonsense.

2. 2

   What do we do first in proof by contradiction?

3. 3

   Let's prove that √2 is irrational (can't be written as a simple fraction).

4. 4

   In the proof about √2, what contradiction did we find?

5. 5

   Try it yourself: Prove that there is no largest even number.

6. 6

   If N is the largest even number, what's wrong with N+2?

7. 7

   That's it! By assuming the opposite and finding a contradiction, you've proven the statement is true. You're a maths detective! 🎉