I view the whole inline evaluation thing to be somewhat of a nasty hack. Generally you are far better off doing something like this:

print "Das ist ", cos($i);

# or
my $funk = 'cos($i)';   # single quotes mean $i is as-is
                        # as opposed to being interpolated
print "Das ist ", eval $funk;

# or
my $coderef = sub { cos(shift) };
print "Das ist ", $coderef->($i);
[download]