Determine the convergence or divergence of the sequence with the given \( n \)th term. If the sequence converges, find its limit. (If the quantity diverges, enter DIVERGES.) \[ a_{n}=(-1)^{n}\left(\frac{n}{n+2}\right) \]
Real Tutor Solution
Answer
Solution
Sign in to Unlock Answers for Free!
A Learning Platform Trusted by Millions of Real Students and Teachers.
Reviewed and approved by the UpStudy tutoring team
Beyond the Answer
To determine the convergence or divergence of the sequence \( a_n = (-1)^{n} \left( \frac{n}{n+2} \right) \), we first analyze the absolute value of the term without the alternating factor: \[ \left| a_n \right| = \frac{n}{n+2} \] As \( n \) approaches infinity, we examine the limit of this absolute value: \[ \lim_{n \to \infty} \frac{n}{n+2} = \lim_{n \to \infty} \frac{1}{1 + \frac{2}{n}} = 1 \] Since this limit is equal to 1 and not approaching 0, we know that \( \left| a_n \right| \) does not converge to 0. Now, let's consider the behavior of the sequence \( a_n \): - When \( n \) is even, \( a_n \) takes the positive value \( \frac{n}{n+2} \). - When \( n \) is odd, \( a_n \) takes the negative value \( -\frac{n}{n+2} \). Thus, as \( n \) increases, the sequence oscillates between values that approach 1 and -1: \[ \lim_{n \to \infty} a_{2n} = 1 \quad \text{and} \quad \lim_{n \to \infty} a_{2n+1} = -1 \] Since the sequence does not settle on any one value and oscillates indefinitely, the overall conclusion is that the sequence diverges. Thus, the final answer is: DIVERGES