Difference between revisions of "Number e and compound interest"

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Suppose you invest some amount for a period of time at effective rate of interest
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Suppose you invest some amount <math> P </math>  for a period of time (that can be a week, month, year etc.) at effective rate of compound interest <math> i. </math> At the end of one such period you have <math> P +iP = P(1+i)</math> accumulated in your account. If you keep your investment for two such periods, the value in your account will be <math> P(1+i) + i[P(1+i)] = P(1+i)^2. </math> In general, if the investment is for <math> n </math> periods, at the end your account will have accumulated <math> P(1+i)^n. </math>
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Suppose, for simplicity, that one period of investment is one year. Suppose further that you invest <math> P = 1 </math> for the period of one year, and the rate of interest is 100% or, equivalently, <math> i = 1 </math> (this means that the amount you invested will double at the end of the year, which, of course, rarely occurs in practice). Alternatively, you

Revision as of 15:43, 3 April 2022

Suppose you invest some amount [math]\displaystyle{ P }[/math] for a period of time (that can be a week, month, year etc.) at effective rate of compound interest [math]\displaystyle{ i. }[/math] At the end of one such period you have [math]\displaystyle{ P +iP = P(1+i) }[/math] accumulated in your account. If you keep your investment for two such periods, the value in your account will be [math]\displaystyle{ P(1+i) + i[P(1+i)] = P(1+i)^2. }[/math] In general, if the investment is for [math]\displaystyle{ n }[/math] periods, at the end your account will have accumulated [math]\displaystyle{ P(1+i)^n. }[/math]

Suppose, for simplicity, that one period of investment is one year. Suppose further that you invest [math]\displaystyle{ P = 1 }[/math] for the period of one year, and the rate of interest is 100% or, equivalently, [math]\displaystyle{ i = 1 }[/math] (this means that the amount you invested will double at the end of the year, which, of course, rarely occurs in practice). Alternatively, you