note 87809 added to book.math

Here is a simple number digit counter function, I used it to check if a number is a palindrome or not, Plus a Distance function, slope formula, sum from one to an integer, sum of odd numbers from one to specified number, and last but not least the sum of the squares of the values of the sine of x, and the cosine of y. <?php function digit_count($num){ for($i=0;pow(10,$i)<=$num;$i++){ if(pow(10,$i+1)>$num){ $num_digits = $i+1; } } return $num_digits; } function distance($x_1,$y_1,$x_2,$y_2){ return sqrt(pow($x_1-$x_2,2)+pow($y_1-$y_2,2)); } function slope($x_1,$y_1,$x_2,$y_2){ return ($y_2-$y_1)/($x_2-$x_1); } // example sum(20)=210=1+2+3+...+20 function sum($x){ return ($x)($x+1)/2; } // example odd(15)=225=1+3+5+7+9+...+15 function odd($x){ if(($x%2) == 0){ $x-=1; } $y=($x+1)/2; return pow($y,2); //Same as $y*$y; } function ($x,$y){ if($x=90-$y){ echo "(Sine of $x)^2 + (Cosine of $y)^2=1"; $value = 1; }else{ $value = pow(sin($x),2)+pow(cos($y),2); } return $value; } ?> ---- Server IP: 64.71.164.2 Probable Submitter: 70.45.112.9 ---- Manual Page -- http://www.php.net/manual/en/book.math.php Edit -- https://master.php.net/note/edit/87809 Del: integrated -- https://master.php.net/note/delete/87809/integrated Del: useless -- https://master.php.net/note/delete/87809/useless Del: bad code -- https://master.php.net/note/delete/87809/bad+code Del: spam -- https://master.php.net/note/delete/87809/spam Del: non-english -- https://master.php.net/note/delete/87809/non-english Del: in docs -- https://master.php.net/note/delete/87809/in+docs Del: other reasons-- https://master.php.net/note/delete/87809 Reject -- https://master.php.net/note/reject/87809 Search -- https://master.php.net/manage/user-notes.php