A1: Proof

From the DfE Mathematics AS and A-Level Content (LINK):

Proof by Contradiction

A1-10 Introducing Proof by Contradiction

A1-11 Proving √2 is Irrational

A1-12 Proving √3 is Irrational

A1-13 Proving √3 is Irrational - Alternative

A1-14 Proving the Cube Root of 2 is Irrational

A1-15 Proving there are Infinitely Many Primes

A1-16 Proof by Contradiction Examples