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:
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;
 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?