Math operation in JS

Question

my code is suppose to calculate mortgage payments

var LA = 100000;
var RA=0.07;
var YA=30;

var R = ( RA / 12);
var r = (1 + R);
var Yr = (YA * 12);
var pay = (LA * Math.exp(r,Yr)*R)/(Math.pow(r,Yr)-1);

returns $224.12

which is wrong it needs to be $665.30 payment = [ LA * r^Yr * R ] / [ r ^Yr - 1]

For example:

30 year mortgage for $100,000 at 7% interest (0.07)

0.07 / 12 = 0.00583 (this is R)

30 * 12 = 360 (this is Yr)

1 + 0.00583 = 1.00583 (this is r)

payment = [ $100,000 * (1.00583)^360 * 0.00583 ] / [ (1.00583)^360 - 1 ]

Monthly Payments will be $665.30

any tips?

Answer 1

Use the correct function: Math.pow and not Math.exp.

Also, although square brackets will work, it's only because JavaScript is casting the arrays to strings, and then to numbers. Use parentheses instead.