You can only explain that with "Huffman" if the save space of 'tan' actually allows you to do something else. Besides, for your reasoning to really work, you'd have to sacrifice one of sin or cos. The analogue would really be having 'splice', 'push' and 'unshift', but not 'pop' or 'shift'. ;-)
Re^5: Perl oddities
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To be more clear, the utility of push, et al. justifies their existence. I
claim (without specific evidence) that the trig functions are, in general,
used much less frequently, thus making their expansion a less productive
use of energy.