PHP tan() returns the tangent of an angle given in radians. The examples below show how the call behaves, where it is useful, and which limitations matter.
What Is tan() in PHP?
Returns the tangent of an angle given in radians.
Its call structure is:
tan($num)The arguments identify the values or resources passed to tan(). Read the examples with attention to the type of each supplied argument and to whether the function modifies its input or returns a separate result.
Example 1: Basic Usage
This example introduces tan with a direct call and a small, readable input.
<?php
echo round(tan(0), 4);Output:
0Returns the tangent of an angle given in radians. Near odd multiples of pi/2, the result is numerically unstable.
Example 2: Another Behavior or Input
Compare this input with the previous example: changing the data or option can affect how tan behaves.
<?php
echo round(tan(pi() / 4), 4);Output:
1The changed input illustrates why output may differ with the chosen values or environment. Near odd multiples of pi/2, the result is numerically unstable.
Practical Example: Using the Feature
The following example incorporates tan into a workflow. Values such as paths, connection handles and configuration options must come from trusted application settings.
<?php
$degrees = 30; $result = tan(deg2rad($degrees)); echo round($result, 6);Output:
0.57735In a real application, check each operation result, validate values before use and clean up acquired resources. Near odd multiples of pi/2, the result is numerically unstable.
Important Behavior and Edge Cases
- Purpose: Returns the tangent of an angle given in radians.
- Key limitation: Near odd multiples of pi/2, the result is numerically unstable.
- Failure handling: Check return values and handle invalid inputs and unavailable operating-system or extension features where relevant.
Comparison With Related Functions
| Function or Approach | Best Fit |
|---|---|
tan() | Returns the tangent of an angle given in radians. |
sin() | Computes the sine of an angle instead of its tangent. |
Common Beginner Mistakes
| Mistake | Correct Approach |
|---|---|
| Near odd multiples of pi/2, the result is numerically unstable. | The correct approach depends on this behavior: Near odd multiples of pi/2, the result is numerically unstable. |
| Ignoring errors or cleanup after the operation. | Validate inputs and check each result; close files, restore settings or release resources when the operation requires it. |
Key Takeaways
- Returns the tangent of an angle given in radians.
- Near odd multiples of pi/2, the result is numerically unstable.
- Use the examples as starting points, and adapt environmental paths, resources and permissions rather than assuming fixed results.
tan is useful when its specific behavior fits the problem. The safest implementations combine the correct API with input validation, error checking and resource cleanup.