help for calculating math func.

[exedat]

hi,this is my program but i cant find the result ®

 

<?php

function float($r) {

for ($r=0 ; ; $r++) {


$kissi =  sqrt(1+4*(pow($kissi,2))*pow($r,2))  /  sqrt( pow( (1-pow($r,2)),2)+4*pow($kissi,2)*pow($r,2)) ;

if ($kissi==0.2) {

 break;
 }

}
echo $r ;
}
?>

 

 

http://www.wolframalpha.com/input/?i=0.2+%3D+sqrt%281%2B4*%28pow%280.2%2C2%29%29*pow%28r%2C2%29%29++%2F++sqrt%28+pow%28+%281-pow%28r%2C2%29%29%2C2%29%2B4*pow%280.2%2C2%29*pow%28r%2C2%29%29

 

i find the result like wolfram alpha pls help me...

[silkfire]

Your $kissi variable is null (not defined) so you can't use it until you have given it a value;

[btherl]

What exactly are you trying to do?  Are you trying to solve the equation for r?

[btherl]

Is this what you want?

 

<?php
float(2.93653);

function float($r) {
        while (true) {
                $kissi =  sqrt(1+4*(pow($kissi,2))*pow($r,2))  /  sqrt( pow( (1-pow($r,2)),2)+4*pow($kissi,2)*pow($r,2)) ;
                print "kissi: $kissi\n";

                if (abs($kissi - 0.2) < 0.00001) {
                        break;
                }
        }
        echo $r ;
}

 

There were a few problems - the "for" loop was resetting $r to 0, and you need to allow a small error when testing floating point numbers for equality.  Output is this:

 

kissi: 0.131178362464
kissi: 0.164754658597
kissi: 0.181082009573
kissi: 0.189658683627
kissi: 0.194298231975
kissi: 0.196842376102
kissi: 0.198247114247
kissi: 0.199025558919
kissi: 0.199457788156
kissi: 0.199698040948
kissi: 0.199831663857
kissi: 0.199906006228
kissi: 0.199947374871
kissi: 0.199970397253
kissi: 0.19998321034
kissi: 0.199990341676
2.93653

[exedat]

i want calculate complex functions and get the result like wolframalpha.com but probably php cant calculate complex func.

 

i want to try calculate for example ; 0.2=x2 +3x or x2+3x=0.2 , php cant calculate this. calculate that ; x= blabla but i cant push the "x" to the left side  alone cause of x is not 1 value    i'm so wondering wolframalpha how is calculate and get result ...

[btherl]

php can't solve equations - all it can do is follow your instructions exactly.  You can program an algorithm for solving equations in php though.  The code you wrote appears to converge on 2 for the real solutions to that equation.

 

Yes, php can't handle complex numbers natively.  You will need to either use or write a library that handles complex arithmetic.  You can google for "php complex number class", that has some results, though I don't know how good they are.