Mathematics

Mathematics

Problem

Let 0<r<10<r<1 and a>0a>0. Consider the geometric progression with first term aa and common ratio rr. Which statement about the partial sums SnS_n (sum of first nn terms) is always true? a) SnS_n decreases with nn and tends to 00. b) SnS_n increases with nn but never exceeds a1−r\dfrac{a}{1-r}. c) SnS_n increases with nn and eventually equals a1−r\dfrac{a}{1-r} for some finite nn. d) SnS_n increases without any upper bound.

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