Translating math formula JavaScript Help

Greetings

I am currently in the process of learning javascript and been working on working on this small simple project that calculates economic formula instantly. I managed to get 7 out of 8 formula to work but got stuck on the last one. I was wondering if some could please show me what I did wrong or how to fix my errors. I will post the formula below.

Formula is Finding Future Value (F) given Gradient Value (G),

Interest (I), and year (N).

F / G: = 1 / N - N / (1 + I)^N - 1

My Problem is when I added value G = 10, I = 10, N =10

I get a result of 93.73 which is wrong. Where i calculate 37.31 as correct.

When I do G =1, I = 10, N = 10.

I get a result of 3.73, which is correct.

Regardless of what I do I can't seem to fix it. Any help and advice is very appreciated. Thank you very much.

Code:

function fvg () {

power = document.form.gradient.value * (1 / (document.form.rate.value / 100)) - (document.form.year.value) / (Math.pow((1 + (document.form.rate.value / 100)), document.form.year.value) - 1);

document.form.amount.value = Math.round(power * 100) / 100;

document.form.interest.value = Math.round((document.form.amount.value - document.form.gradient. value) * 100) / 100;

}