How do you use summation notation to expression the sum #0.1+0.4+1.6+...+102.4#?
Judging by the first three terms, they don't share a common difference, so it will not be an arithmetic series; however, we should test the ratio of the terms to determine whether we have a geometric series:
So, we have a geometric series with the first term
Since the series ends at
So, the series starts at