2012-09-22

A bearded man in a green shirt sits at a small round table with a cup of coffee, holding a spoon, looking glum. A woman, shown in profile close-up on the right, leans toward him and says, "I'm making a you substitution." A caption below reads: "It's hard getting dumped by a mathematician." The joke puns on the calculus technique of u-substitution (substituting a variable u). In the votey aftercomic, a close-up of the now-grinning bald, bearded man as the woman says, "Now you're 'dx'!" — referencing the dx term that accompanies u-substitution, the punchline reducing him to a mere differential.