Math::BigFloat

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


my $pi =  Math::BigFloat->bpi(10);

my ($run,$theta) = (3,8);

my $radians = Math::BigFloat->new($theta * $pi / 180);

#my $rise = Math::BigFloat->new($run * tan($radians)); 
my $rise = Math::BigFloat->new($run * (sin($radians) / cos($radians)))
+;

say "rise is $rise";

#rise is 0.42162250410717434055
[download]

Here is what I came up with for an equivalent. Supposedly the Math:: packages offer up to arbitrary precision or accuracy. The tan function is not working for me though, I get an error: Can't call Math::BigFloat->_cartesian, not a valid method at /usr/local/share/perl/5.14.2/Math/Complex.pm line 928. This inspired me to use a trig identity in real, well, almost real life for the first time..

So, if you can install packages, (Math::Trig and Math::BigFloat come with Perl) you can use those modules for really high accuracy calculations. If you don't then you might have to lose some accuracy

In that case..

#!/usr/bin/env perl
use strict;
use warnings;
my $pi = 355/113;
my ($run,$theta) = (3,8);

my $radians = $theta*$pi/180;
my $rise = $run * (sin($radians) / cos($radians));

say "rise is $rise";
#rise is 0.421622540378273
[download]