Question

If x = 3 + √8, find the value of x^2+1/x^2

Answer 1

Step-by-step explanation:

x = 3+ √8

x = (3+√8)(3-√8) / (3-√8)

x = (9 -8) / (3-√8)

x = 1/ (3 -√8)

Or we can write 1/x = (3-√8)

Put the value and find out

x² +(1/x²) = x² + (1/x)²

So x² + 1/ x² = (3 +√8)² + (3 -√8)²

= 9+6√8+8 + 9–6√8+8

= 34. Ans.

Answer 2

Answer

= 34

Step-by-step explanation:

x = 3 + root8

1/x = 1/3+ root8

1/x = 1/3+root8   x   3-root8/3-root8

1/x= 3-root8/3square-square of root8

1/x=3-root8/9-8

therefore 1/x = 3-root 8

xsquare + 1/xsquare =

3+root8 the whole square     +       3-root8 the whole square

[9+6root8+8]   +  [9-6root8+8]

17 + 6root8 + 17 - 6root8

+6root8 and -6root8 will get cut

= 17 + 17

= 34