If x= 3 + √8. Find the value of x² + 1/x²?
- 36
- 32
- 34
- None of these
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.
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