Show that the average of the Ui’s taken over an entire cycle of a full-period LCG is  – 1/...

Show that the average of the U_i’s taken over an entire cycle of a full-period LCG is  – 1/(2m). [Hint: for a positive integer k, Euler’s formula states that 1 + 2 + … + k = k(k + 1)/2.]