SOLUTION: Find the sum of the first n terms of the following arithmetic sequence. a1 = 2, d = 2; n = 5.

Algebra ->  Sequences-and-series -> SOLUTION: Find the sum of the first n terms of the following arithmetic sequence. a1 = 2, d = 2; n = 5.       Log On


   

Question 380157: Find the sum of the first n terms of the following arithmetic sequence.
a1 = 2, d = 2; n = 5.
Answer by rfadrogane(214) About Me  (Show Source):
You can put this solution on YOUR website!
Find the sum of the first n terms of the following arithmetic sequence.
a1 = 2, d = 2; n = 5.
Sol'n:

S = n/2[2a1+(n-1)d]
= (5/2)[2(2)+(5-1)2]
= (5/2)[4+8]
= (5/2)(12)
S = 30 --answer