This program uses the compound interest formula which gives the amount in an account for a principal of P, invested
for t years at an interest rate of r (decimal) p.a. and calculated n times per
year. It will find any of the values in the formula, given the values of
all the others.
|This program will produce a table comparing the
growth of an investment for a given annual interest rate under compound
and simple interest.
Interest rate is entered as a decimal
(eg. 25% should
be entered as 0.25)
|When the program terminates you can press NUM to
see the table or PLOT to see a graph. The axes are automatically set up by
Note: Sequences U1 and U2 in the Sequence
aplet are overwritten by this program and the Sequence aplet becomes the
|This program will calculate the length of a loan,
displaying the result in the NUM view and automatically setting up the
PLOT view to show the result. Payments can be made annually, quarterly or
|eg. I borrow $10,000 at 7.5% p.a. interest,
compounded quarterly and repay it at a rate of $200 per quarter, beginning
on Jan 1, 1990.
|As can be seen in the NUM view right, the equations
are set up to go to zero at the completion of the loan, rather than
continuing into negative numbers.
The time is shown in column U1, with 1990.03
corresponding (for example) to the 3rd quarter of 1990. In the case
of this loan, it is repaid during the 2nd quarter of 2027. The exact
length is also given, in this case as 37 years and 3 months. It should be
noted that the final payment will be very slightly incorrect due to the
fact that interest is calculated for the entire quarter instead of being
done 'pro-rata' as the bank would.
Note: Sequences U1 and U2 in the
Sequence aplet are overwritten by this program and the Sequence aplet
becomes the active one.
|This program will use the I=PRT formula for simple
interest to find the principle, the amount of interest paid, the interest
rate, the time, the total paid, or the weekly, monthly or quaterly
repayment amount. The user must supply all values except the one being