Question

x=
$3 + \sqrt{8}$
find
${x}^{2} + \frac{1}{ {x}^{2} }$
​

Answer 1

Explanation:

x=3+

3 x2

=(3+ 8 )

2 =9+8+6

8 =17+6

8x 2 + x 21

=(3+

8

)

2

+

(3+

8

)

2

1

⇒17+6

18

+

17+6

8

1

⇒

17+6

8

(17+6 8) 2 +1 ×

(17−6 8 )

(17−6 8 )

⇒

289−288

(17+6 1 ) 2

(17−6 )+(17−68 )

⇒(289−288)(17+6 8)+17−6 8

⇒17+6

8+17−6 8 =34