If x - \(\frac{1}{x}\) = 2\(\sqrt{2}\)
then find the value of x2 - \(\frac{1}{x^2}\).
Answer & explanation
Correct answer: option 3
⇒ If x - \(\frac{1}{x}\) = a then x + \(\frac{1}{x}\) = \(\sqrt {a^2 + 4}\)
Here,
x - \(\frac{1}{x}\) =2\(\sqrt{2}\), then
⇒ x + \(\frac{1}{x}\) = \(\sqrt {(2\sqrt{2})^2 + 4}\) = 2\(\sqrt{3}\)
Formula → x2 - y2 = (x + y) (x - y)
⇒ x2 - \(\frac{1}{x^2}\) = (x + \(\frac{1}{x}\)) (x - \(\frac{1}{x}\))
= 2\(\sqrt {3}\) × 2\(\sqrt{2}\)
= 4\(\sqrt{6}\)