Calculation Using Exponentiation

• Dec 21, 2006, 13:55
grahowler
Calculation Using Exponentiation
I am trying to figure out how to duplicate a, financial, calculation that uses the caret, Exponentiation.

Here's the formula...

A = 0.0755
B = 34
C = 50000
D = 22448

result = ((C-D)*A/12)/(1-(1+A/12)^(-B))+D*A/12

It calculates loan repayments based on interest rate (A), number of payments (B), total loan amount (C) and a residual amount (D).

This calculation will work when the caret (Exponentiation) is used, however Javascript doesn't use that.

I have found examples of how to do Exponentiation, like this:
Code:

```function powmod(base,exp,modulus) {  var accum=1, i=0, basepow2=base;  while ((exp>>i)>0)  {   if(((exp>>i) & 1) == 1){accum = (accum*basepow2) % modulus;};   basepow2 = (basepow2*basepow2) % modulus;   i++;  };  return accum; }```
This function comes from here http://www.math.umbc.edu/~campbell/N...pt.html#PowMod (some handy stuff there) but I can't replicate the calculation I have posted using a function like that.

Anyone know how to do this?

Thanks!
• Dec 21, 2006, 19:37
mrhoo
Math.pow(n,p)
n is the number to be raised to a power
p is the power(exponent)

Math.pow(10,3) returns 1000
• Dec 22, 2006, 05:37
El Fuego
So here we get

n = ((C-D)*A/12)/(1-(1+A/12)

p = (-B))+D*A/12

:)