(adsbygoogle = window.adsbygoogle || []).push({}); Help with "series"

so I have learned how to do different problems of series.

but theres this problem that I spent hours last night but could not come up with anything.

which is-

∞

∑ n/2^(n-1)

n=1

so from there i was able to take out 2 and end up with: 2 n /(2^n)

i dont know how to do after that. however, i thought about doing (1/2)^n but then again it does not make sense to me.

help needed. i will appreciate that. thanks

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# Homework Help: Help with series

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