If $100 is deposited in a savings account that earns interest at an annual rate of 4 1/2% compounded continuously, what is the value of the account at the end of two years?

2 Answers
Jun 8, 2018

See alan_n

Jun 9, 2018

$109.42$109.42

Explanation:

The formula for compound interest calculation where the compounding occurs continuously is:

A_t = Pe^(rt)At=Pert

Where:

A_tAt is the amount after tt years
PP is the principal amount
rr is the annual interest rate
ee is Euler's number approx 2.718282.71828

In this example: P=$100, r=4.5% = 0.045P=$100,r=4.5%=0.045

:. P_2 =100xx e^(0.045xx2)

approx 100 xx 2.71828^0.09

=$109.42 To 2D

NB: For those interested in the derivation of the formula it stems from the limit definition of e. Also see: http://www.milefoot.com/math/calculus/limits/LimitDefinitionOfE10.htm