Thanks to visit codestin.com
Credit goes to perldoc.perl.org

You are viewing the version of this documentation from Perl 5.28.1. View the latest version
sqrt EXPR
sqrt

Return the positive square root of EXPR. If EXPR is omitted, uses $_. Works only for non-negative operands unless you've loaded the Math::Complex module.

use Math::Complex;
print sqrt(-4);    # prints 2i