Find the nth term of the sequence 3, 6, 10, 15, 21.....
A
\(\frac{n(n - 1)}{2}\)
B
\(\frac{n(n + 1)}{2}\)
C
\(\frac{(n + 1)(n + 2)}{2}\)
D
n(2n + 1)
Verified Correct Answer: C.
Step-by-Step Mathematical Solution
\(\frac{(n + 1)(n + 2)}{2}\)
If n = 1, the expression becomes 3
n = 2, the expression becomes 6
n = 4, the expression becomes 15
n = 5, the expression becomes 21
Source: Myschool Past Questions Archive (Record #31015)