What will be the Mean? If

The mean of x and 1/x is M. Then the mean of x2 and 1/x2 is:

  1. M2                                                              
  2. M2-2
  3. 4M2-2
  4. 2M2-1
Monis Rasool Professor Asked on 7th July 2015 in Maths.
Add Comment
  • 1 Answer(s)

    Answer: (4) 2M2 – 1
    Explanation:-
    Given-
    (x + 1/x)/2 = M
    Then, x + 1/x = 2M             …………………. (1)
    Square on both side of equation (1)
    (x + 1/x)2 = x2 + 1/x2 + 2 x X x 1/X
    (2M)2 = x2 + 1/x2 + 2             {from equation (1) x + 1/x = 2M }
    4M2 = x2 + 1/x2 + 2
    4M2 – 2 = x2 + 1/x2
    mean of x2 + 1/x2)/2 = (4M2 – 2)/2
    = 2M2 – 1

    Hence, the answer is (4) 2M2 – 1.

    Anurag Mishra Professor Answered on 8th July 2015.
    Add Comment
  • Your Answer

    By posting your answer, you agree to the privacy policy and terms of service.