Question

If X=3+√8, find X square + 1/x square​

Answer 1

Given :-

• x = 3 + √8

To find :-

• x² + 1/x²

Solution :-

According to Question,

• x = 3 + √8
• 1/x = 1/3-√8
• 1/x = 1(3+√8)/(3+√8)(3-√8)
• 1/x = 3+√8/3²-(√8)²
• 1/x = 3+√8/9-8
• 1/x = 3 + √8

So that ,

• x² + 1/x²
• (x + 1/x)² - 2
• ( 3+√8+3-√8)²-2
• 9² - 2
• 81 - 2
• 79