Mortgage payment algorithm

[DerPflug]

I'm trying to get a monthly payment algorithm to work but I seem to be messing up with the order of precedence or something. I'm not sure. The algorithm is:

(P * R * (1 + R)^L)/((1 + R)^L - 1)

P = principal = $1000
R = interest rate = %10
L = length of loan = 12 months

With these values the monthly payment should be 87.92.

I currently have:
payment = (P * R * pow(1 + R,L))/(pow(1 + R,L) - 1);
but this doesn't seem to work. Any ideas?

 

[PerFnurt]

R is 0.10, not 10, right?

/Per
[sub]Nerdy signatures are as lame as the inconsistent stardates of STTNG.[/sub]

 

[DerPflug]

Yes, R is .10. My problem was that I wasn't dividing the interest by 12.