Question

2. Explain why the Ratio Test can or cannot be used to determine whether the series isconvergent.(a)[infinity]Qn=1(−1)n(b)[infinity]Qn=1sin(n)(c)[infinity]Qn=12n+1n2n−1(d)[infinity]Qn=1(n!)2(2n)!

Answer 1

I think so its A [infinity]Qn=1(−1)n