TAN(): the tangent of a given angle (in radians)

$angle = deg2rad(45);
echo tan($angle); // approximately 1

float tan(float $num)

$num is the angle in radians. The return value is its tangent.

<?Php
echo tan(M_PI); // Output is  0 
echo "<br>";
echo tan(M_PI / 2); // Very large finite value due to floating-point approximation 
echo "<br>";
echo round(tan(M_PI / 3), 2); // Output is 1.73
echo "<br>";
echo tan(M_PI / 4); // Output is 1 
?>

deg2rad() with TAN()

<?Php
echo tan(deg2rad(0)); // Output  is 0
echo "<br>";
echo tan(deg2rad(90)); // Very large finite value because 90° is represented approximately 
echo "<br>";
echo tan(deg2rad(180)); // Tiny floating-point approximation of 0
?>

Example: Handling Tan of 90 Degrees

$angle = 90;
echo tan(deg2rad($angle));  // Very large finite value; tangent is mathematically undefined at 90°

Example: Calculating Slope of a Triangle

$angle = 45;
$adjacent = 10;
$opposite = $adjacent * tan(deg2rad($angle));  // Output: 10 (Height of the triangle)
echo $opposite;

Example: Calculating Tan for Small Angles

$angle = 30;
echo tan(deg2rad($angle));  // Output: 0.57735026918963

Example: Tan of Negative Angles

$angle = -45;
echo tan(deg2rad($angle));  // Output: -1

Example: Using Tan to Find Height from Distance and Angle

$angle = 30;  // Angle of elevation
$distance = 100;  // Distance from object
$height = $distance * tan(deg2rad($angle));  // Calculate height
echo $height;  // Output: 57.735026918963

Plotting sine curves by using PHP GD function with deg2rad()

Subhendu Mohapatra

Author & Instructor at plus2net

I write and maintain practical tutorials on Python, PHP, SQL, JavaScript, HTML, jQuery, and web development at plus2net. The tutorials focus on clear explanations, working examples, and code that readers can test and adapt while learning.

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