How can beginners in PHP avoid errors when working with mathematical functions like cos()?

Beginners in PHP can avoid errors when working with mathematical functions like cos() by ensuring that input values are in the proper format (radians instead of degrees) and checking for common errors like division by zero. It's also important to handle any potential errors that may arise, such as using the is_nan() function to check for NaN (Not a Number) results.

$angle = deg2rad(45); // Convert degrees to radians
if ($angle != 0) {
    $result = cos($angle);
    if (!is_nan($result)) {
        echo "Cosine of 45 degrees is: " . $result;
    } else {
        echo "Error: Invalid input for cosine function.";
    }
} else {
    echo "Error: Division by zero.";
}