The sum of the members of a finite arithmetic progression is called an arithmetic seriesFor example consider the sum. In simple words summation notation helps to write a short form for the addition of a very large number of data sequences. S_n 1234cdots n displaystyle sum_k1n k.
The elementary trick for solving this equation which Gauss is supposed to have used as a child is a rearrangement of the sum as follows.
Common difference -4 Derivation of Formulas Let d common difference a 1 first term a 2 second term a 3 third term a m. The formula for the n -th partial sum Sn of a geometric series with common ratio r is given by. This expression means sum the squared values of x starting at x1 and ending with xn. The limits of summation are often understood to mean i 1 through n.