Continuously compunded interest

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Homework Statement


The island of Manhattan was sold for $24 in 1626. Suppose the money had been invested in an account which compounded interest continually.

a) How much money would be in the account in the year 2005 if the yearly interest rate was:
i: 5%? ii: 7%

The Attempt at a Solution



I put the numbers into the function P0ert and got

i:24e.05(379) and ii:24e.07(379)

but when I put that in my calculator I get VERY large numbers:

i: 4074662794 and ii: 7.980752573E12

For some reason, I don't think the homework answers would be such ridiculously large numbers. Did I do this right?
 
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The numbers are ridiculously large but that doesn't mean they are wrong. Exponential growth is fast and 379 years is a ridiculously long time. I think you are correct.
 
There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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