Question: If the sum of the first n terms of an arithmetic progression is given by S_n = 3n^2 + 2n, what is the common difference?
Options:
Correct Answer: 3
Solution:
The sum of the first n terms S_n = n/2 * (2a + (n-1)d). By differentiating S_n with respect to n, we can find the common difference. The common difference is 3.