Class 9th Additional Questions Q. If the mean of x and 1/x  is M then find the mean of x²  and 1/x². Sol Mean of x and 1/x Mean = 1/2[x+1/x] M = 1/2[x+1/x] [x+1/x] = 2M  ........(1) Mean of x² and 1 / x² = 1/2[x² + 1/x² + 2–2] adding and subtracting 2 in x² + 1/x²  = …