.asp exponentiation formula to .php, help required.

Trent_Hatred

Hi There,

I'm in the process of converting a .asp based site to PHP, and I'm having a problem with a particular formula.

In .asp, exponentiation is done using "^", and in PHP apparently the function to use is "pow". That being said, I'm not entirely sure how to re-write the following formula...

Original .asp formula:
$tmpDenominator = 1 - ((1 + $periodicIR) ^ ($numberOfPayments));

Could anyone offer some insight? I just can't seem to match the result with the original .asp formula, and my eyes are starting to hurt.

:eek:

Thanks much,

kevinsequeira

from the manual

to compute the exponent from given power and base

<?
$exp=3;
$base=2;

$power=pow($base,$exp);
print("$base raised to the power of $exp returns $power\n");

$exp2=log10($power)/log10($base);
print("if power of expression is $power and base is $base than the exponent is $exp2\n");
?>

so i guess in your case it would be

$tmpDenominator = 1 - ((1 + $periodicIR) ^ ($numberOfPayments));

$tmpDenominator = 1 - (pow((1 + $periodicIR) , ($numberOfPayments)));

does it work ??
reg
kevin

Trent_Hatred

Hi Kevin,

I've read that information at php.net as well, and unfortunately, I'm still lost as to how I apply that to my formula.

I've tried the following incorporating the "pow" function in place of the "^", as well as a whole myriad of other variations and nothing seems to produce a similar result.

Trent_Hatred

Hi again Kevin,

Tried the formula you provided and unfortunately, it didn't produce the same result, though it did produce something considerably closer to anything that I've had so far.

kevinsequeira

the reverse

$tmpDenominator = 1 - (pow( ($numberOfPayments),(1 + $periodicIR)));

any better ?

im not sure abt the asp syntax, lemme look it up

reg
kevin

Trent_Hatred

Hi Kevin,

I think I may have figured it out using the following:

$tmpDenominator = 1 - (pow((1 + $periodicIR),((0 + $numberOfPayments))));

The above is exactly like you're first formula, however for some reason it won't accept $numberOfPayments as the exp directly. Once I added the 0 + to the equation, the numbers miraculously came out proper.

I have a feeling however that other formulas based on this will likely not be proper... but that's just me being negative. 😉

Thanks for all you're help, I definately would not have figured that out alone.

Sincerely,