Compound interest describes how an investment grows when interest is added not only to the initial amount but also to previously earned interest. With a 4% annual compound interest rate, each year’s balance becomes 1.04 times the previous year’s amount. This growth forms a geometric sequence, where the common ratio of 1.04 represents the consistent multiplier applied to each term.To analyze whether an infinite sum of such terms reaches a finite value or grows indefinitely, mathematicians use...