I have been trying for quite some time now to stump my dad on just one question. I've tryed out physics, Astronomy & Cosmology, Mathematics, Philosophy, logic, tecnology, almost every subject! It is getting to the point where i stay up late on the internet trying to find something. can anyone suggest a question please?

mattmns
Do you need to understand the problem? What is your dad's background?

Gold Member
Perhaps you can give us some examples of the questions you've asked and some answers he's provided. It porably wouldn't be fair to ask him to porivde a rigourous mathematical proof of the shape of an electron D orbital.

Homework Helper
how do you know your dad's answer is accurate, not necessarily bogus, but he might be off the mark

heman
Shippo said:
I have been trying for quite some time now to stump my dad on just one question. I've tryed out physics, Astronomy & Cosmology, Mathematics, Philosophy, logic, tecnology, almost every subject! It is getting to the point where i stay up late on the internet trying to find something. can anyone suggest a question please?

Well there is a question in Mathematics which My teacher asked me when i was in 11th class and i haven't come across anybody who could suggest or even hint a way out!

integration of x*Sec(x)

mattmns said:
Do you need to understand the problem? What is your dad's background?
well he has done a lot of things...he was a mathmatiton, he designs software, was an Engineer, has a masters in physics um...thats all i can think of at the time being.

GCT said:
how do you know your dad's answer is accurate, not necessarily bogus, but he might be off the mark
I don't know, witch is pretty stupid. If i eventuoaly find a question that stumps him and he says the rong answer he won't beleve that its rong. :grumpy:

Gold Member
I can't get my father to acknowledge that there is no such thing as centrifugal force. He insists (or did 10 years ago) that the bucket on the string will go flying away at an angle instead of tangential to the circle.

Some day ... some day ... I will prove it to him. I will probe him wrong. I will prove them ALL wrong. They laughed at me. They mocked me. But I will show them. I will how them my POWER. They will flee, like ants under my feet. I will...

What? Is this thing still on? **

Last edited:
Mental Gridlock

whozum
"What is the purpose of meaning?"

-Dexter's lab

moose
Do the questions have to be about logic, or can they be history questions? Surely he won't know all of history :D

Mental Gridlock
Is he physcic? Ask him what number your'e thinking of. Better yet ask him what commercial will be on next.

Homework Helper
heman said:
Well there is a question in Mathematics which My teacher asked me when i was in 11th class and i haven't come across anybody who could suggest or even hint a way out!

integration of x*Sec(x)

The integral of x*sec(x) cannot be expressed as an elementary function- meaning usual nice finite combinations of exponentials, logarithms, polynomials, trig functions, etc. This is the same situation as the more common e^(-x^2).

Mental Gridlock
Tell him to go on jeapordy. He should do awesome. Except you said he answered every question right, I don't know how he'd fare given only answers. But he should go on some quiz show for big bucks!

Homework Helper
If you had a tunnel that went straight through the Earth from New York City to Tokyo and dropped an unpowered train in the New York end, how long would it take to roll to Tokyo (assuming the tunnel was a sealed vacuum and the Earth was stationary)? It would speed up until the tunnel reached the midway point between New York and Tokyo and then slow down at the same rate. It would take about 42 minutes for it to gently roll to a stop in Tokyo.

How about from New York City to Sydney Australia? About 42 minutes.

New York City to Los Angeles? About 42 minutes.

Even if he's not stumped, he'll at least enjoy explaining why.

This link, http://www.physics4all.co.il/open.php?link=628 [Broken], explains the problem. Just scroll down to "A Boring Problem".

Some of the other problems might give you some ideas, as well.

Last edited by a moderator:
ask him for a valid argument of creationism :biggriN;

marlon
Shippo said:
I have been trying for quite some time now to stump my dad on just one question. I've tryed out physics, Astronomy & Cosmology, Mathematics, Philosophy, logic, tecnology, almost every subject! It is getting to the point where i stay up late on the internet trying to find something. can anyone suggest a question please?
I made some quizzes here on PF, ask him these questions...just scroll down to the quizzes : https://www.physicsforums.com/journal.php?s=&action=view&journalid=13790&perpage=10&page=8 [Broken]

marlon

Last edited by a moderator:
Gold Member

marlon
Or ask him who the REAL inventors of special relativity were. The guys, who came up with this idea PRIOR to Einstein.

Or ask him why there are only eight gluons ?
Or ask him who really invented heliocentrism
...check the quizzes
marlon

Mental Gridlock said:
Tell him to go on jeapordy. He should do awesome. Except you said he answered every question right, I don't know how he'd fare given only answers. But he should go on some quiz show for big bucks!

sorry i phrased it rong insted of right it should be *correct. And yes he would be good on jepordy

Mental Gridlock
Right and correct mean the same thing, I meant you said he answered every QUESTION correct, but Jeopardy doesn't use questions, they use answers, so he could be screwed. It was just a lame attempt at a joke nevermind it!

Homework Helper
honestrosewater said:
That's too easy. Women want a man that can dilate his eyes at will.

JonF
honestrosewater said:
money?

Homework Helper
Gold Member
Dearly Missed
BobG said:
That's too easy. Women want a man that can dilate his eyes at will.
Why should I bother to learn how to dilate my EYES at will?
Yet another example of the inscrutable female psyche..

Staff Emeritus
Gold Member
BobG said:
That's too easy. Women want a man that can dilate his eyes at will.
An optometrist? Well, yeah, they do make good money and work regular hours; not a bad choice.

Staff Emeritus
Ask him what your thinking right now. Even if he does guess what your thinking tell him he's wrong anyway.

whozum

Staff Emeritus
whozum said:

Watch out, his head might explode.

Gold Member
don't put him on jeopardy, put him on millionare. you pick: $20,000 or$1,000,000

Gold Member
arildno said:
Why should I bother to learn how to dilate my EYES at will?
Yeah, we really want someone with a huge e.g.o. anyway

heman
shmoe said:
The integral of x*sec(x) cannot be expressed as an elementary function- meaning usual nice finite combinations of exponentials, logarithms, polynomials, trig functions, etc. This is the same situation as the more common e^(-x^2).

I know its solution and i very well know its solution contain polylog function and other adhoc complex functions,but i don't care about the complexity involved!
Do you know how to solve it??
I have tried this question more than any question i can think of!

I don't agree with what you say about e^(-x^2)
Its a very easy question which can be solved trivially with the help of Polar Coordiantes and further with change of variables!

I guess you must have been pointing to x^x,its solution can't be written in form of elementary functions!

heman
honestrosewater said:

Tell me what do you want??

Gold Member
heman said:
Tell me what do you want??
If you have to ask, you don't really want to know.

Hey, I'm getting the hang of this inscrutable psyche stuff

heman
honestrosewater said:
If you have to ask, you don't really want to know.

Hey, I'm getting the hang of this inscrutable psyche stuff

So...Hmmmm...Ok...Well ...Yeah

I have observed all through that women reveal only when they are asked!

Homework Helper
heman said:
I know its solution and i very well know its solution contain polylog function and other adhoc complex functions,but i don't care about the complexity involved!
Do you know how to solve it??
I have tried this question more than any question i can think of!

Write sec(x) in terms of exponentials, $$sec(x)=2/(e^{ix}+e^{-ix})$$, then a change of variables, $$e^{ix}=t$$. Using partial fractions you can then write the integral in terms of dilog say, which is an integral you can't express in elementary terms. This isn't really anymore satisfying than the original form though, but I guess this is the find of thing you're looking for. I wouldn't call rearranging this integral into some other arbitrary looking integral, that necessarily has no elementary solution, "solving" anything, but that's just me.

Or if you like you can express x*sec(x) as a power series and integrate that (keeping mind of the interval of convergence). Again, this is somewhat unsatisfying and not in elementary terms (which implies a finite number of terms).

heman said:
I don't agree with what you say about e^(-x^2)
Its a very easy question which can be solved trivially with the help of Polar Coordiantes and further with change of variables!

You can work out $\int_{-\infty}^{\infty}e^{-x^2}dx$ exactly by polar coordinates or other tricks. This is not what I said was impossible. You cannot express an antiderivative of $$e^{-x^2}$$ in terms of elementary functions (for the usual definition of "elementary function"), this is not debatable. There is a difference between expressing an antiderivative in terms of elementary functions and evaluating a definite integral exactly.