Question

if x=3+√8,find the value x square plus 1 upon x square
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Answer 1

Given: x =3+√8

Squaring both sides .

=>x^2 =(3+√8)^2.

=> x ^2 = (3)^2+(√8)^2+2×3×√8.

=> x^2 = 9+8+6√8.

.°. x^2 = 17+6√8 .

=> 1/x^2 = 1/17+6√8

=>1/x^2=(17-6√8)/(17+6√8)(17-6√8)

=> 1/x^2 =17-6√8/289-288.

.°. 1/x^2 =17-6√8.

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.°. x^2+1/x^2

=17+6√8+17-6√8

=34.