If x^4 + 1/x^4 = 47, find the positive value of x + 1/x.

A2

B3

C4

D5

Explanation

(x^2 + 1/x^2)^2 = x^4 + 1/x^4 + 2 = 47 + 2 = 49 => x^2 + 1/x^2 = 7. Then (x + 1/x)^2 = 7 + 2 = 9 => x + 1/x = 3.

Exam Relevance

Topic: Algebra
Subtopic: Identities

Submitted by: mcqstutor Team More Mathematics MCQs →