Discovery of E Name: Compound Interest – Interest Paid on The
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Discovery of E Name: Compound Interest – interest paid on the principal of an investment and any previously earned interest. A -> P-> r-> n-> t-> 1) An investment account pays 4.2% annual interest compounded monthly. If $2500 is invested in this account, what will be the balance after 15 years? Set up the equation: A = 2) Find the balance of an account after 7 years if $700 is deposited into an account paying 4.3% interest compounded monthly. John Bernoulli discovered something by studying a question about compound interest. (Who is John Bernoulli? Johann Bernoulli (27 July 1667 – 1 January 1748) was a Swiss mathematician and was one of the many prominent mathematicians in the Bernoulli family. He is known for his contributions to infinitesimal calculus and educated Leonhard Euler in his youth. (Source: Wikipedia) Ready to be John Bernoulli? An account starts with $1.00 and pays 100 percent interest per year. If the interest is credited once, at the end of the year, the value of the account at year-end will be $2.00. What happens if the interest is computed and credited more frequently during the year? Write your prediction here: ______________________________________________________ ___________________________________________________________________________ Let’s do solve this mathematically using compound interest rate formula. Frequency (number of compounding Equation Total periods each year.) Once a year $2.00 Twice a year $2.25 Yay! We made $0.25 more! Compound bimonthly Compound monthly Compound weekly Compound daily Compound hourly Compound secondly What did you observe from the above table? Can we ever reach $3? _________________________ ________________________________________________________________________________ Bernoulli noticed that this sequence approaches a limit with larger n and, thus, smaller compounding intervals. Compounding weekly (n = 52) yields $2.692597..., while compounding daily (n = 365) yields $2.714567..., just two cents more. The limit as n grows large is the number that came to be known as e; with continuous compounding, the account value will reach $2.7182818.... You have just discovered e! 1) What kind of number is e? 2) Why is “e” an important number in math? 3) What does “LN” represent? .