x² - 2√6 – 5 = 0 হলে, (x + 1/x) এর মান-

x² - 2√6 – 5 = 0
or, x² = 2√6 + 5 = 3 + 2.√3.√2 + 2
or, x² = (√3 + √2)²
or, x = √3 + √2
so, 1/x = √3 - √2
so, x + 1/x = √3 + √2 + √3 - √2
so, x + 1/x = 2√3