“What’s your sine? It must be pi/2 because you’re the 1.”
Pick-up lines are a huge form with multiple genres within them. Pick-up lines are hardly ever used seriously–that is, to actually pick up dates. They’re told humorously, usually to highlight a clever play on words. The romantic message is used as a stock message along which to frame the wordplay, which is the real focus of a pick-up line joke. The combination of the two produces a corny and awkward and therefore funny effect. The nerdy pick-up line goes one step further to juggle an extra requirement–the incorporation of overly intellectual content. As nerd-dom is traditionally unsexy, this adds an extra level of amusement, not to mention cleverness. It’s a way for nerds to say, hey, we need lovin’ too.