Introduction to sequences

9000063809

Level: 
B
Given the sequence \(\left ( \frac{1} {n(n+1)}\right )_{n=1}^{\infty }\), find the recurrence relation for this sequence.
\(a_{n+1} = \frac{n} {n+2}a_{n},\ a_{1} = \frac{1} {2}\)
\(a_{n+1} = \frac{n} {n+1}a_{n},\ a_{1} = \frac{1} {2}\)
\(a_{n+1} = \frac{n+1} {n} a_{n},\ a_{1} = \frac{1} {2}\)
\(a_{n+1} = \frac{n+1} {n+2}a_{n},\ a_{1} = \frac{1} {2}\)

9000063810

Level: 
A
Consider the sequences \(\left (a_{n}\right )_{n=1}^{\infty }\) and \(\left (b_{n}\right )_{n=1}^{\infty }\) where \(a_{n} = 2^{n}\) and \(b_{n} = n^{2} - 1\), respectively. Identify a true statement in the terms of these sequences.
\(a_{3} = b_{3}\)
\(a_{2} = b_{2} + 2\)
\(a_{4} = b_{4} - 2\)
\(a_{5} = b_{5} - 8\)