∑m3e−βusn=e0+e−βus+e−β2us+⋯Converge paraA=11−e−βus
A=11−e−βus
Step 1 :Given summation: ∑m3e−βusn=e0+e−βus+e−β2us+⋯
Step 2 :Recognize this as a geometric series with a common ratio of e−βus
Step 3 :Calculate the sum of the geometric series: A=11−e−βus
Step 4 :A=11−e−βus