Question

if a=9+4√5 and b=1/a then find the value of a^3+b^3

Answer 1

Hi! Hope this answer helps you.......

Answer 2

given, a=9+4√5 & b=1/9+4√5
therefore ..b=1×9-4√5/9+4√5×9-4√5
b=9-4√5/81-80
b=9-4√5

now....
a^3+b^3= (9+4√5)^3+(9-4√5)^3
= 9^3 +4√5^3+3ab(a+b) +9^3-4√5^3-3ab(a-b)
=all the rest is in pic!...