\(x + \frac{1}{x} = \sqrt 5 \) হলে, \(x3 + \frac{1}{{x3}}\) = এর মান কত ?
Correct Answer: Option A
দেওয়া আছে, \(x + \frac{1}{x} = \sqrt 5 \)
\(x3 + \frac{1}{{x3}} = (x + \frac{1}{x})3 - 3.x.\frac{1}{x}(x + \frac{1}{x})\) (
= \((\sqrt 5 )3 - 3\sqrt 5 \)
= \(\sqrt {5.(} \sqrt 5 )2 - 3\sqrt 5 \)
= \(5\sqrt 5 - 3\sqrt 5 \) (5টি \(\sqrt 5 \) থেকে 3টি \(\sqrt 5 \) বিয়োগ করতে হবে ) = \(2\sqrt 5 \)
Download our app for free and access thousands of MCQ questions with detailed solutions