What is the formula for the number of powers of 2 under an arbitrary number ?
If the arithmetic mean of n numbers x1 , x2 , ... , xn is M and A is any arbitrary number , then show that sigma -LRB- Xi - A -RRB- 2 = sigma -LRB- Xi - M -RRB- 2 + n -LRB- M-A -RRB- 2 ?