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PHP for Maths
Posted: Wed Jun 01, 2005 4:07 am
by Parody
Hmm....
Any ideas what is wrong with this?:
Code: Select all
<?php
$weight = 3150;
$HP = 500;
$answer = (6.9446 X ($weight / $HP)^.2841);
print "$answer";
?>
I get this error:
Code: Select all
Parse error: syntax error, unexpected T_STRING in c:\program files\apache group\Apache\htdocs\mile.php on line 4
Thanks in advance

Posted: Wed Jun 01, 2005 4:11 am
by timvw
Please read chapther 15. Operators in the manual (
http://www.php.net/manual). Please notice that the operator for multiplication is * instead of X.
Posted: Wed Jun 01, 2005 4:13 am
by Parody
Thanks, I'm tired

Posted: Wed Jun 01, 2005 4:21 am
by Parody
Ok, it works but its getting the wrong answer
This is the equation I am trying to use:
6.9446 X (weight / HP)^.2841
This is what I have:
Code: Select all
<?php
$weight = 3826;
$HP = 294;
$answer = (6.9446 * ($weight / $HP)^.2841);
print "$answer";
?>
According to the mathematical equation (not the php one) with the same values within weight and HP the answer is : 14.396
The PHP equation gets : 90.
I think it is the ^ . What does php interpret by this symbol?
Posted: Wed Jun 01, 2005 4:25 am
by timvw
RTFM.
Posted: Wed Jun 01, 2005 4:29 am
by Parody
Read the F***ing Manual?
I F***ing did, lol, sorry
This is what it says:
$a ^ $b Xor Bits that are set in $a or $b but not both are set.
And that means what?
That is the only time it is refrenced throughout the manual.

Posted: Wed Jun 01, 2005 4:30 am
by Ross2376
Use:
Code: Select all
<?php
$weight = 3826;
$HP = 294;
$answer = (6.9446 * pow(($weight / $HP), .2841));
print "$answer";
?>
The ^ does not mean raised to in PHP. Use the pow() function instead.
pow(base, exponent);
Posted: Wed Jun 01, 2005 4:33 am
by Parody
Thanks.
Posted: Wed Jun 01, 2005 1:46 pm
by wwwapu
Parody wrote:$a ^ $b Xor Bits that are set in $a or $b but not both are set.
And that means what?
This is basic logic, dear Watson. Search for "logic circuits" or "boolean algebra"
http://www.allaboutcircuits.com/vol_4/chpt_7/7.html is quite understandable explanation on xor.