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PHP atanh() Function
Definition and Usage
The atanh() function returns the inverse hyperbolic tangent ratio of given given parameter. In other words, the return value of atanh() is hyperbolic tangent of given parameter. A inverse hyperbolic tangent function is defined as .
atanh(x) = 0.5Xlog((1+x)/(1-x))
This function returns a float value .
Syntax
atanh ( float $arg ) : float
Parameters
| Sr.No | Parameter & Description |
|---|---|
| 1 | arg A floating point value whose inverse hyperbolic tangent is to be calculated |
Return Values
PHP atanh() function returns inverse hyperbolic tangent ratio of given parameter.
PHP Version
This function is available in PHP versions 4.x, PHP 5.x as well as PHP 7.x.
Example
Following example calculates atanh(pi/4) and returns which is also the result of formula definition −
<?php $arg=M_PI_4; $res=atanh($arg); echo "atanh(pi) = " . $res . "
"; $val = 0.5*log((1+$arg)/(1-$arg)); echo "using formula = " . $val; ?>
Output
This will produce following result −
atanh(pi) = 1.0593061708232 using formula = 1.0593061708232
Example
Following example computes atanh(Π/10) −
<?php
$arg=M_PI/10;;
$val=atanh($arg);
echo "atanh(" . $arg . ") = " . $val;
?>Output
This will produce following result −
atanh(0.31415926535898) = 0.32515348134414
Example
Let's check find out atanh(0). It returns 0 −
<?php
$arg=0;
$val=atanh($arg);
echo "atanh(" . $arg . ") = " . $val;
?>Output
This will produce following result −
atanh(0) = 0
Example
For parameter = 1 atanh() function returns INF
<?php
$arg=1;
$val=atanh($arg);
echo "atanh(" . $arg . ") = " . $val;
?>Output
This will produce following result −
atanh(1) = INF
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