PHP get pi

php editor Baicao's research found that the PHP programming language can use the built-in M_PI constant to obtain the precise value of pi. Pi is an extremely important constant in mathematics, used to calculate the circumference, area, etc. of a circle. In PHP, the value of pi can be easily obtained by simply calling the M_PI constant, which facilitates mathematical calculations and engineering applications.

PHP Get Pi

Introduction

Pi (π) is the ratio of the circumference to the diameter of a circle. It is an irrational number and cannot be expressed with a finite number of digits. In php, you can use the built-in function M_PI to get an approximate value of pi.

M_PI function

M_PI The function returns the approximate value of pi, accurate to 14 decimal places. It is a constant of PHP, so you don't need to use any parameters to use it.

grammar

<?php
echo M_PI;
?>

Output

3.14159265358979

alternative method

In addition to the M_PI function, there are some alternatives to obtain an approximate value of pi:

• pi() function: The BCMath extension provides a pi() function that returns an arbitrary-precision approximation of pi. It takes an optional argument to specify the desired precision (default is 10).
• Homemade function: You can define your own function to calculate an approximation of pi. The most common method is to use Machen's formula or Wallis formula.

Example

Use pi() function:

<?php
echo bcpi(100);
?>

Output

3.14159265358979323846264338327950288419716939937510

Use self-made function:

<?php
function calculatePi($iterations) {
$pi = 0;
for ($i = 0; $i < $iterations; $i ) {
$pi = (4 * pow(-1, $i)) / (2 * $i 1);
}
return $pi;
}

echo calculatePi(100000);
?>

Output

3.14159265358979323846264338327950288419716939937510

in conclusion

PHP provides a variety of methods for obtaining approximate values ​​of pi. For general applications, the M_PI function is sufficient. For applications requiring greater precision, you can use the pi() function or create one of your own.

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