Thonau's diary

This diary is made for my lovely honey, thonau. I hope you like it!

Monday, February 07, 2005

Mathematical Excuses

For students not to do homework:

- I accidentally divided by zero and my paper burst into flames.
- I could only get arbitrarily close to my textbook, I couldn't actually reach it.
- I have the proof, but there isn't room to write it in this margin.
- I have a solar-powered calculator, and it was cloudy.
- I locked the paper in my trunk, but a four-dimensional dog got in and ate it.
- I couldn't figure out whether i AM the square root of negative one or i IS the square root of negative one.

For professors not to give out proof:

-Proof by omission: "The reader may easily supply the details" or " The other 253 cases are analogous"
-Proof by funding: " How could three different goverment agencies be wrong?
-Proof by deferral: " We'll prove this later in the course"
-Proof by intimidation: " Trivial"
-Proof by seduction: " Convince yourself that this is true"
-Proof by accumulated evidence: " Long and diligent search has not revealed a counterexample"

(Reteln and Dundes)

Mathematical Folklore

Q: Why did the mathematician name his dog "Cauchy"?
A: Because he left a residue at every pole.

Q: What is a topologist?
A: Someone who can't distinguish between a doughnut and a coffee cup.

Q: Why didn't Newton discover group theory?
A: Because he wasn't Abel.

Q: What do you get if you cross an elephant and a banana?
A: /elephant/*/banana/*sin(theta).

Q: What is a polar bear?
A: A rectangular bear after a coordinate transform.

Q: What does a topologist call a virgin?
A: Simply connected.

Q: How many mathematicians does it take to change a light bulb?
A: 0.999999.......

Q: Why does a chicken cross the road?
A: It was forced to do so by the chicken-hole principle.

Q: How many analysts does it take to screw in a light bulb?
A: Three. One to prove existence, one to prove uniqueness, and one to derive a nonconstructive algorithm to do it.

Theorem: All dogs have nine legs.
Proof: Would you agree that no dogs have five legs? Would you agree that a dog has four legs more than no dog? 4+5=???

Theorem: All positive integers are interesting.
Proof: Assume the contrary. Then there is a lowest noninteresting positive integer. But, hey, that's pretty interesting! A contradiction.