Practicing Success

Target Exam

CUET

Subject

General Test

Chapter

Quantitative Reasoning

Topic

Algebra

Question:

If x8 + 1 - 34x4 = 0, x > 0, then

find (\(\frac{x^6 + \frac{1}{x^6}}{2}\))

Options:

198

188

99

100

Correct Answer:

99

Explanation:

Given, x8 + 1 - 34x4 = 0

taking x4 common, then

⇒ x4 + \(\frac{1}{x^4}\) = 34

⇒ x2 + \(\frac{1}{x^2}\) = \(\sqrt {34 + 2}\) = 6

⇒ x6 + \(\frac{1}{x^6}\) = (6)3 - 3 × 6 = 198

So, (\(\frac{x^6 + \frac{1}{x^6}}{2}\)) = \(\frac{198}{2}\) = 99