Q. Use the Ratio Test to determine whether the series is convergent or divergent.n=1∑∞(−1)n−12nn33nIdentify an
Identify general term: Identify an as the general term of the series, which is an=(−1)n−1(3n)/(2nn3).
Apply Ratio Test: Apply the Ratio Test by finding the limit of the absolute value of anan+1 as n approaches infinity.
Calculate an+1: Calculate an+1 which is (−1)n(3n+1)/(2n+1(n+1)3).
Find absolute value: Now, find the absolute value of an+1/an=∣∣2n+1(n+1)3(−1)n(3n+1)⋅(−1)n−1(3n)2nn3∣∣.
Simplify expression: Simplify the expression to get \left|\frac{\(3\)}{\(2\)}\left(\frac{n^{\(3\)}}{(n+\(1\))^{\(3\)}}\right)\right|.
Take limit: Take the limit as \(n approaches infinity of ∣∣23((n+1)3n3)∣∣.
Calculate final limit: Since the degrees of the polynomials in the numerator and denominator are the same, the limit is the ratio of the leading coefficients. So, the limit is 23.