Q. n=1∑∞n!n+1Study if it converges or diverges using Ratio test.
Write general term: Write down the general term of the series. an=n!n+1
Apply Ratio Test: Apply the Ratio Test to determine convergence or divergence.We need to find the limit of ∣an+1/an∣ as n approaches infinity.
Calculate an+1: Calculate an+1.an+1=(n+1)!n+2
Set up ratio: Set up the ratio ∣∣anan+1∣∣.\left|\frac{a_{n+\(1\)}}{a_n}\right| = \left|\frac{\frac{n+\(2\)}{(n+\(1\))!}}{\frac{n+\(1\)}{n!}}\right|
Simplify the ratio: Simplify the ratio.\(\newline∣∣anan+1∣∣=∣∣(n+1)(n+2)⋅((n+1)!)n!∣∣∣∣anan+1∣∣=∣∣(n+1)2(n+2)∣∣
Take limit: Take the limit of the ratio as n approaches infinity.n→∞lim∣∣(n+1)2n+2∣∣
Evaluate limit: Evaluate the limit. limn→∞∣∣(n+1)2n+2∣∣=limn→∞∣∣n+11∣∣
Limit is 0: The limit is 0 because as n gets larger, (n+1)1 approaches 0.limn→∞∣∣(n+1)1∣∣=0
Ratio Test conclusion: Since the limit is less than 1, the Ratio Test tells us the series converges.