Question

If x = 9 +4V5 , find the value of x2 +
1/
x2

Answer 1

Answer:

x2 + 1 / x2 = 23

Step-by-step explanation:

Given :

( x + 1 /x ) = 5

We need to find x2 + 1 / x2

( x + 1 / x )2 = 25

= x2 + 1 / x2 + 2 (x)(1/x) = 25

= x2 + 1/x2 + 2 = 25

= x2 + 1 / x2 = 25 – 2

= x2 + 1 / x2=23

Hence x2 + 1 / x2 = 23