What is the n-th term of the sequence 2, 6, 12, 20...?
A
4n - 2
B
2(3n - 1)
C
n2 + n
D
n2 + 3n + 2
Verified Correct Answer: C.
Step-by-Step Mathematical Solution
Given that 2, 6, 12, 20...? the nth term = n\(^2\) + n
check: n = 1, u1 = 2
n = 2, u2 = 4 + 2 = 6
n = 3, u3 = 9 + 3 = 12
∴ n = 4, u4 = 16 + 4 = 20
Source: WAEC / JAMB / NECO Classroom Archive (Record #31322)