BigFloat

#!/usr/bin/perl
use strict;
use warnings;
use Math::BigFloat;
use feature 'say';

my $m = Math::BigFloat->new('1.673E-27');
my $c = Math::BigFloat->new('3E8');
my $k = Math::BigFloat->new('1.38E-23');
my $T = Math::BigFloat->new('1.4E11');
my $mu = Math::BigFloat->new('-0.1E-10');
say my $E = - $m * $c * $c;

my $e = Math::BigFloat->bone()->bexp();
my $x1 = ($E - $mu) / ($k * $T);
my $x2 = Math::BigFloat->bone();
say $x2 / ($x2 + $e ** $x1);