PHP errror in cos() function-CodePudding

In an exercise I did :

<?php
$initial = '555';
$a = octdec($initial);
echo $a . "\n";

$b = deg2rad($a) . "\n";
echo $b;

$c = cos($b). "\n"; *(line 9)*
echo $c;

and it does show the correct answer, as well as an error:

365
6.3704517697793
0.99619469809175
PHP Notice:  A non well formed numeric value encountered in /home/ccuser/workspace/hg2pmf/index.php on line 9

if I change line 9 with : $c = cos(6.3704517697793). "\n"; the message of error disappear. Why can't I use the $ inside the cos() when in deg2rad() works perfectly?

CodePudding user response：

The problem is that on this line...

$b = deg2rad($a) . "\n";

You are adding the new line onto the end of the calculated value.

So remove it and your value will be the number you expect...

$b = deg2rad($a);

As a help, I use

declare(strict_types=1);

and I get the error...

Fatal error: Uncaught TypeError: cos(): Argument #1 ($num) must be of type float, string given in which shows how it's changed the value from a number to a string.