☰ Contents1.3 · Revisiting irrational numbers76/101

Worked: 3√2 is irrational

Assume 3√2 = a/b. Then √2 = a/(3b), a ratio of integers — so √2 would be rational. It isn't. Contradiction — 3√2 is irrational.

Check yourself

Quick check
Prove that 3 + 2√5 is irrational.