Question

I am trying to write a math equation with PHP. The equation I need to write is:

(.0054 * 260000) / (1-1.0054^-360)

This equals: 1639.958570 (On my calculator)

With the script I am writing I have it as such:

$dec = .0054;
$amount = 260000;
$months = 360;

$equation = ($dec * $amount) / (1 - (1 + $dec)^-$months);

print $equation;

The answer I am getting when I do this is “-3.9”

Any idea what I’m doing wrong?

Answer 1

Try using the pow() function:

$equation = ($dec * $amount) / (1 - pow(1 + $dec, $months * -1));