What is the sum of the arithmetic sequence that starts with 3 and 9 and ends with 15, with a total of 26 terms?
The sum of an arithmetic sequence can be found using the formula: Sn = (n/2) * (a + l) Where: Sn = Sum of the first n terms n = Number of terms a = First term l = Last term In this case, we have the following: a = 3 (the first term) l … Read more