php task 15624 echo strrev br task1 21 27 echo res log sin cos task3 a

<?php
//task 2
$n = 15624;
echo strrev($n)."<br>";

//task1
$a = 3;
$b = 21;
$m = 3.27;

echo $res = ($m*log($m) + $a * sin($a * $m)) / $b * cos($b);

//task3
$arr = array(1, 2, 3);

$arrSum = array_sum($arr);
echo ($arrSum / count($arr));

//task4

?>