I think both are cute. I actually started a thread sometime back about the mountain climber/mosquito joke because it requires 3 domains of knowledge to get (Math of cross products, another name for mountain climbers, and another name for disease carriers in biology). I love jokes that require lots of specific knowledge, and having them explained to me doesn’t ever ruin the fun 
Thanks. Glad you enjoyed it. I now remember a slightly better version of the story. The two profs each put their twenty down on the table. When she answers “x squared over 2” both comment on how thats the right answer! Then as she leaves the table she grabs both twenties and says “and plus, of course, an arbitrary constant C”.
I think the joke’s funny. Technically my diploma says I’m supposed to be a sociologist, but I do a lot of math for fun.
I have a similar joke that I use to identify any physicists in the room:
Q: Why did the cat fall off the roof when he caught laryngitis?
A: Because he lost his mu.
For those who enjoy the explanations 
:
The Greek letter mu is used in physics for the coefficient of static friction, which is the measure of how “grippy” a surface is when you’re standing still on it. Static friction is often greater than sliding friction, which is why sometimes you have to give something an extra tug to start it moving. With no mu, there’s not enough force to keep the kitty cat sitting on a slanted roof, so the poor thing succumbs to gravity and slides down the slope.
Sagittariuses are “known” to be goal oriented (in classic imagery, the archer aiming an arrow at a target)…but we (yes, me too) are *so *focused on the target, we often miss the mess we’re creating in pursuit of that goal. And to add to the fun, we’re not always so great at pursuing a goal long term. Great at start ups, but tend to leave messes in our wake, and then we’re not much interested in actually finishing that project and cleaning up after ourselves, because another project has caught our attention.
Virgoes, of course, are all about clean up. Meticulous and detail oriented, a Virgo is a Sag’s best friend. (Literally, in my case, which is why I love that joke so much. My Virgo bff has saved my butt sooooooo many times!) Whether it’s cleaning up after a messy kitchen experiment or consoling a heartbroken love interest when the Sag’s interest flits away, the Virgo is there to deal with the disaster in her wake.
So it only takes one Sag to change a light bulb, but she’s going to leave a heck of a mess behind, and her faithful Virgo pal will tidy up behind her. 
…and if anyone berates me for talking astrology on the Dope or asks for a cite, I’m going to find something shiny in another thread to post about instead, and leave the rest of the job to a passing Virgo. 
It won’t be any Capricorn. Capricorns don’t believe in astrology.
It’s not funny because it’s wrong. The cross product should be a vector, and there’s no unit vector in the answer.
Q: What’s a polar bear?
A: A rectangular bear after a co-ordinate transformation.
Now that’s funny - and having it explained didn’t even spoil the fun…
but the sine theta thingy - still waiting…
Why did the bear dissolve when he jumped in the water?
He was a polar bear.