A Good Nerd Joke

This joke was told to me at a meeting by Allen Mincer:

Two physicists are discussing the ignorance of 'everyday people' at a restaurant. One says that people aren't that stupid, while the other is convinced that most people don't know basic math. They make a bet that the waitress won't even be able to do the simple integral of x^2. They put $10 down.

The negative physicist goes to the washroom before the waitress can come by. The positive physicist sneaks over to the waitress, and says "My friend is going to ask you a question. Whatever he says just say 'x-cubed over three' " and the waitress protests, and he insists "just say x-cubed over three".

Soon, the 2nd physicist comes back, and the waitress brings over the bill. The negative physicist says "Ma'am, I was wondering if you could tell me what the integral of x^2 is?". She hastily slams the bill on the table and angrily says "x-cubed over three!". The negative physicist is surprised and hands over the ten-spot.

As the waitress walks away she says under her breath "...plus a constant!".