Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

If \(\sqrt {x}\) + \(\frac{1}{\sqrt {x}}\) = \(\sqrt {6}\) 

Find x6 + \(\frac{1}{x^6}\).

Options:

2702

5404

1351

1021

Correct Answer:

2702

Explanation:

Formula →  x6 + \(\frac{1}{x^6}\) = (( x + \(\frac{1}{x}\))2)3

ATQ,

\(\sqrt {x}\) + \(\frac{1}{\sqrt {x}}\) = \(\sqrt {6}\)

⇒ (\(\sqrt {x}\) + \(\frac{1}{\sqrt {x}}\))2  = (\(\sqrt {6}\) )2 

⇒ x + \(\frac{1}{x}\) + 2 = 6

⇒ x + \(\frac{1}{x}\) = 4

⇒ x2 + \(\frac{1}{x^2}\) = (4)2 - 2 = 14

⇒ (x2 + \(\frac{1}{x^2}\))3 = (14)3

⇒ x6 + \(\frac{1}{x^6}\) = (14)3 - 3 × 14 = 2744 - 42 = 2702