Question . (2 marks) Add up the last three digits of your student id number, we refer to this sum as s (e.g.: 2012080127 = s = 1+2+7 = 10). Similarly, add up all the digits of your student id number and we refer to this bigger sum as t (e.g.: 2012080127 t =2+0+1+2+0 +8+1+2+7 23). Write down a series for which the set of points æ ER where the series converges is equal to (s, t], and prove it!