Question

lf the mean of x,1/x is m then the mean of x³,1/x³​

Answer 1

The correct option (a) [(8m3 – 6m)/2]   Explanation:  [{x + (1/x)}/2] = m ⇒ x + (1/x) = 2m also x3 + (1/x3) = [x + (1/x)]3 – 3[x + (1/x)] ∴ mean of x3 & (1/x3) is given by (1/2)[x3 + (1/x3)]   = (1/2)[{x + (1/x)}3 – 3{x + (1/x)}] = (1/2)[(2m)3 – 6m]  = (1/2)(8m3 – 6m).  if-the-mean-of-x-and-1-x-is-m-then-mean-of-x-3-and-1-x-3-is-a-8m-3-6m-2