Determine whether the series is convergent or divergent by expressing sn as a telescoping sum (as in example 7). ∞ cos 7 n2 − cos 7 (n + 1)2 n = 1

6. sarah saved $12.75 every week for a number of weeks, w. she received an additional $25 during the last week in which she saved money. write and solve an equation to find the number of weeks, w, for which sarah had saved money if she has $114.25 now.