# Computing the Future Value of various things

Someday I'll give the formulae's I'm using in a "nice" form. For now,
here they are:
FVA = b*((1.0+(r/100.0)/12.0)**(n));
FVIFA = a*((((1.0+(r/100.0)/12.0)**(n))-1.0)/((r/100.0)/12.0));

where
- "a" is the amount per month,
- "b" is the beginning balance,
- "r" is the interest rate (percentage), and
- "n" is the number of months.

The rate of return is calculated using:
Worth = b*((1.0+(r/100.0)/12.0)**(n)) +
a*((((1.0+(r/100.0)/12.0)**(n))-1.0)/((r/100.0)/12.0));

where the value of "r" (the rate of return) is determined by trial and
error.
# Computing Monthly Mortgage Payments

The formulae to compute the montly mortgage payment is:
Monthly Payment = t/((1.0-(1.0/((1.0+r)**(n))))/r);

where
- "t" is the amount of the morgage,
- "n" is the number of years, and
- "r" is the monthly interest rate (percentage). To
obtain r, simply divide the mortgage rate by 12. (e.g. the value of r
for an interest rate of 7.2 percent would be 0.072/12 = 0.006).