Question

If a = 3 + √5 / 2 , then find the value of a2 + 1 / a2

The Answer i got was 11√5

Answer 1

A = 3+✓5/2

Therefore,

a²+1/a² = (3+✓5)²+1/(3+✓5)²

= 9+5/4+1/9+5/4 = 14+4/4/9+5/4 = 18/14 = 9/7