Introduction to sequences

1003107301

Level: 
B
We are given the sequence \( \left( \frac{n+1}n \right)^{\infty}_{n=1} \). Find the recursive formula of such sequence.
\( a_1=2\,;\ a_{n+1}=a_n\frac{n(n+2)}{(n+1)^2},\ n\in\mathbb{N} \)
\( a_1=2\,;\ a_{n+1}=a_n\frac{n(n+2)}{(n+1)},\ n\in\mathbb{N} \)
\( a_1=1\,;\ a_{n+1}=a_n\frac{n(n+2)}{(n+1)^2},\ n\in\mathbb{N} \)
\( a_1=2\,;\ a_{n+1}=a_n\frac{n(n-2)}{(n+1)^2},\ n\in\mathbb{N} \)

9000063809

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