PHP - 如何使用bcsqrt()函數取得任意精確度數字的平方根？

string bcsqrt($num_string, $scale)

<?php
   // input numbers with arbitrary precision
   $num_string = "22";

   // below bcsqrt function calculates the square root
   $result= bcsqrt($num_string);
   echo "Output without scale value: ", $result;
?>

Output without scale value: 4

<?php
   // input numbers with arbitrary precision
   $num_string = "22";

   //scale value 3
   $scale="3";

   // below bcsqrt function calculates the square root
   $result= bcsqrt($num_string, $scale);
   echo "Output with scale value: ", $result;
?>

Output with scale value: 4.690