Search found 118 matches

by TheWaterBear
Wed Apr 04, 2012 3:01 pm UTC
Forum: Mathematics
Topic: Simplify
Replies: 15
Views: 4552

Re: Simplify

I got this comparatively bizarre answer \frac{1}{16(x^2+y^2)^2} which I suppose could be a bit more elegantly expressed as \frac{1}{(4x^2+4y^2)^2} I'm currently working back through my work to see where I went wrong (I've already found one mistake, as the above is actually my second...
by TheWaterBear
Wed Oct 12, 2011 8:35 pm UTC
Forum: Coding
Topic: Making a GUI
Replies: 24
Views: 4341

Re: Making a GUI

C# / ASP.NET have a bunch of built in objects (like Drop downs, Textboxes, Buttons for users to push, etc) in Visual Studio that's really easy to use (drag and drop them onto your GUI/webpage). The reason I'm suggesting it is that the jump from C++ to C# is easy (the jump to ASP.NET from HTML, not ...
by TheWaterBear
Wed Oct 12, 2011 7:20 pm UTC
Forum: Coding
Topic: Making a GUI
Replies: 24
Views: 4341

Re: Making a GUI

The interface just needs to be able to have a few drop down menus for selecting a few user inputs, then write those values to a file; then the user should hopefully be able to click a button and the executable will run, taking all of the info it needs from the created text file. Are you supposed to...
by TheWaterBear
Tue Oct 11, 2011 3:37 am UTC
Forum: Coding
Topic: Making a GUI
Replies: 24
Views: 4341

Re: Making a GUI

How interactive does this GUI need to be? It's pretty easy to create a GUI that lets you set command line parameters or initializes an input data / configuration file & then runs the program. (Does modern FORTRAN even accept command line parameters? I haven't used it in decades. ) I often use t...
by TheWaterBear
Tue Oct 11, 2011 12:38 am UTC
Forum: Mathematics
Topic: Your favorite "tricky" integrals?
Replies: 46
Views: 14944

Re: Your favorite "tricky" integrals?

Integral of sin(x)/(sin(x)+cos(x)) from 0 to pi/2 Heh, I like that one. Would you believe: I argue that I can do that in my head, and the answer is pi/4 ? That's very nifty. I did it on paper just to make sure I did it right, but it came out in about 3 lines. The temptation do use the half-angle su...
by TheWaterBear
Mon Oct 10, 2011 3:04 am UTC
Forum: Mathematics
Topic: Your favorite "tricky" integrals?
Replies: 46
Views: 14944

Re: Your favorite "tricky" integrals?

skullturf wrote:
TheWaterBear wrote:Integral of sin(x)/(sin(x)+cos(x)) from 0 to pi/2


Heh, I like that one.

Would you believe: I argue that I can do that in my head, and the answer is
Spoiler:
pi/4
?


correct ;)

I like it because you *can* carry out the integration, but it has a very simple solution ^^
by TheWaterBear
Sun Oct 09, 2011 3:50 pm UTC
Forum: Mathematics
Topic: Your favorite "tricky" integrals?
Replies: 46
Views: 14944

Re: Your favorite "tricky" integrals?

Integral of sin(x)/(sin(x)+cos(x)) from 0 to pi/2
by TheWaterBear
Fri Oct 07, 2011 9:07 pm UTC
Forum: Mathematics
Topic: Should i change the limits?
Replies: 3
Views: 682

Re: Should i change the limits?

Afif_D wrote:z=sec x,
dz= sec x. tan x. dx

Notice anything about that? You defined a variable who's derivative is the function you're trying to integrate... :)
by TheWaterBear
Fri Oct 07, 2011 5:13 am UTC
Forum: Coding
Topic: Making a GUI
Replies: 24
Views: 4341

Re: Making a GUI

Yeah...I got my BS in nuclear, only using C++/Fortran for computations, so I have no background at all in making user interfaces. Would Visual Basic let me create something that is platform independent? I was hoping to make something that is platform independent.
by TheWaterBear
Thu Oct 06, 2011 9:43 pm UTC
Forum: Coding
Topic: Making a GUI
Replies: 24
Views: 4341

Re: Making a GUI

Ok, so I was a little misdirected before.

What should I use to create an interface (just something simple, with drop down menus and such) that can create a text file and then run an executable?
by TheWaterBear
Fri Sep 23, 2011 12:47 am UTC
Forum: Coding
Topic: Making a GUI
Replies: 24
Views: 4341

Making a GUI

As part of my Master's work, I need to make a GUI for a code...that is written in FORTRAN. To be honest, I've never done anything like this, so I'm looking for suggestions of languages that would be able to create a GUI to interface with FORTRAN code. I've coded in C++, FORTRAN, and have a little ex...
by TheWaterBear
Mon Aug 29, 2011 6:45 am UTC
Forum: Mathematics
Topic: Conditional Probability Question
Replies: 16
Views: 4210

Re: Conditional Probability Question

Have you tried making a diagram? When I first started doing these kinds of problems, it was really helpful for me to map it out like a tree diagram. With it mapped out, you can easily identify what numbers are relevant for your calculation. I attached the diagram I made for this problem. The first t...
by TheWaterBear
Fri Aug 19, 2011 6:17 am UTC
Forum: Mathematics
Topic: Weighted coin question and probability
Replies: 10
Views: 2180

Re: Weighted coin question and probability

FixMyIgnorance wrote:Yes I know it would involve some sort of Bayesian probability or a null hypothesis test of sorts, but I never knew how to actually compute it


Right, but that would imply that you test how weighted you believe the coin is weighted to begin with, as Conman pointed out.
by TheWaterBear
Sat Aug 13, 2011 3:42 pm UTC
Forum: Mathematics
Topic: Choosing an advisor
Replies: 4
Views: 1164

Re: Choosing an advisor

I first made a list of the advisors that were doing research in things that interested me. Then I eliminated people that got their undergrad degree before a certain point, so that the advisor was less likely to retire/die before I finished my studies. With my shortlist in hand, I visited the differe...
by TheWaterBear
Tue Jun 07, 2011 1:09 am UTC
Forum: Mathematics
Topic: Stupid Math/Physics word problem, need help
Replies: 14
Views: 2957

Re: Stupid Math/Physics word problem, need help

While everyone posting is going about it the right way, I would just choose v = 0 and a = 0....

(although, I guess it's not technically moving in a particular direction if v=0.)

EDIT: DOH...completely ignored that the first ship had some negative acceleration, haha.
by TheWaterBear
Sat Apr 30, 2011 7:05 pm UTC
Forum: Mathematics
Topic: Does this problem have a name?
Replies: 4
Views: 1049

Re: Does this problem have a name?

If I have n sets S_1 S_2 \ldots S_n , each with a different number of elements, if I were to form pairs of elements (s_i, s_j) such that each element of the pair is from a different set, how many pairs would I have? For example, if I had sets with 8 and 3 elements respectively, the number o...
by TheWaterBear
Fri Feb 25, 2011 8:58 pm UTC
Forum: Mathematics
Topic: Standard Error Question
Replies: 2
Views: 724

Re: Standard Error Question

So if i have an Ordinary Least Squares regression function of the form: f(x)= Bx + Dx^2 where B and D are constants and X represents sales of a company in dollars. Now X and X^2 each have their own standard errors SE(x) and SE(x^2) and if I convert x into thousands of dollars how do I find the new ...
by TheWaterBear
Mon Jan 31, 2011 6:12 am UTC
Forum: Mathematics
Topic: Does this series converge!?
Replies: 32
Views: 4364

Re: Does this series converge!?

ImTestingSleeping wrote: I only posted because that was bugging me and I wanted a definitive answer.


I honestly thought this thread was just trollin' games.
by TheWaterBear
Fri Jun 18, 2010 3:47 am UTC
Forum: Mathematics
Topic: Question about volume.
Replies: 14
Views: 1522

Re: Question about volume.

Oregonaut wrote:Thank you everyone for your help.

My daughter and I had a fantastic time last night working through the problem. (Even more awesome, she did all the math working while I simply helped guide and measure the dice.)

She wants me to pass along her regards.



dawwwwwww :)
by TheWaterBear
Fri Jun 18, 2010 3:46 am UTC
Forum: Mathematics
Topic: 4 digit code
Replies: 4
Views: 1222

4 digit code

Today, while I was entering the gate code to enter my apartment complex, I had a thought. Ok, so the gate code is 4 digits, followed by enter. The gate doesn't unlock unless you press enter after entering the correct gate code. Now, intuitively, I would think that it would take less tries at guessin...
by TheWaterBear
Fri May 28, 2010 4:57 am UTC
Forum: Mathematics
Topic: Math discovered or invented?
Replies: 110
Views: 18236

Re: Math discovered or invented?

It's our attempt to quantify the world.

Invented.
by TheWaterBear
Tue Jan 05, 2010 10:35 pm UTC
Forum: Mathematics
Topic: The ideal number.
Replies: 70
Views: 8169

Re: The ideal number.

by TheWaterBear
Wed Dec 30, 2009 4:56 pm UTC
Forum: Mathematics
Topic: The ideal number.
Replies: 70
Views: 8169

Re: The ideal number.

t0rajir0u wrote:24.


I thought I was the only one! 24 ftw!
by TheWaterBear
Thu Dec 24, 2009 3:10 am UTC
Forum: Mathematics
Topic: Can't remember what it's called
Replies: 6
Views: 1208

Re: Can't remember what it's called

Quigibo wrote:Your'e thinking of an "ogive". Pronounced "Oh-jive".


That's what it was!! Awesome, thanks :)
by TheWaterBear
Wed Dec 23, 2009 3:32 am UTC
Forum: Mathematics
Topic: Can't remember what it's called
Replies: 6
Views: 1208

Re: Can't remember what it's called

The EGE wrote:Do you mean a logistic function?


It looks similar to that, but it has a different name. This is really bugging me :(
by TheWaterBear
Wed Dec 23, 2009 3:18 am UTC
Forum: Mathematics
Topic: Can't remember what it's called
Replies: 6
Views: 1208

Can't remember what it's called

What's the name of a percentile graph? The one that kind of looks like a stretched out integral symbol.

I think it starts with an "o"

...I think.
by TheWaterBear
Tue Dec 15, 2009 5:08 pm UTC
Forum: Mathematics
Topic: I need a problem
Replies: 7
Views: 1596

Re: I need a problem

jaspervdj wrote:I'm thinking about cryptography ant tranformations in computer graphics.


+1 to cryptography
by TheWaterBear
Sun Dec 13, 2009 6:55 pm UTC
Forum: Mathematics
Topic: From now and on you will call me Doctor!
Replies: 7
Views: 1132

Re: From now and on you will call me Doctor!

EstLladon wrote:I am a PhD now!!!

This friday I defended my thesis "Algorithmic complexity of Lambek calculus fragments".

Wooohoooo!


Congratulation, Dr. :)
by TheWaterBear
Sun Dec 13, 2009 4:09 pm UTC
Forum: Mathematics
Topic: Integrals--Substitution Rule
Replies: 9
Views: 2081

Re: Integrals--Substitution Rule

Hmmm...I ended up getting pi/4. Did I lose a 1/2 somewhere? I ended up getting the same also... We lost a 1/2 somewhere before :) u = x^2 (1/2)du = x dx \int^1_0 x\sqrt{1-x^4}\ dx = \int^1_0 (1/2)\sqrt{1 - u^2}\ du u = sin(t) du = cos(t)dt \int^1_0 (1/2)\sqrt...
by TheWaterBear
Mon Dec 07, 2009 7:14 am UTC
Forum: Individual XKCD Comic Threads
Topic: 0672: "Suggestions"
Replies: 90
Views: 22735

Re: "Suggestions" Discussion

petafile wrote:CollegeHumor did it.

http://www.collegehumor.com/article:1794382


This. A very disappointing Monday comic :(
by TheWaterBear
Mon Nov 23, 2009 2:49 am UTC
Forum: Mathematics
Topic: Help with a PDE
Replies: 3
Views: 651

Help with a PDE

Alright, so this was something we did in class, but I failed miserably at finding the correct answer, so I was hoping someone might be able to help me. We have a square plate, and we know the temperature along all four sides of the plate (picture). Three of the sides are constant, and the other side...
by TheWaterBear
Mon Nov 16, 2009 1:53 am UTC
Forum: Mathematics
Topic: Either I'm crazy or 1 is infinitely close to 0
Replies: 18
Views: 4445

Re: Either I'm crazy or 1 is infinitely close to 0

>.< True also infinitely small number times infinitely large number is infinitely close to 1 not zero. This is why I shouldn't be allowed to post this early my time, I don't think things through. Actually this isn't quite true. Multiplying infinity by something infinitely small is not well defined....
by TheWaterBear
Sat Nov 14, 2009 11:49 pm UTC
Forum: Mathematics
Topic: PDE Solution Methods
Replies: 9
Views: 1534

Re: PDE Solution Methods

colinrmitchell wrote:I have the above mentioned book. I highly recommend it. It is clearly written and easy to refer to. I have used it countless times in my studies.


Good to hear. I just ordered it, so I should have it by Tuesday :D
by TheWaterBear
Sat Nov 14, 2009 8:16 pm UTC
Forum: Mathematics
Topic: PDE Solution Methods
Replies: 9
Views: 1534

Re: PDE Solution Methods

modularblues wrote:Partial Differential Equations for Scientists and Engineers by Stanley J. Farlow.


From the reviews on Amazon, it seems to be a pretty good book, especially for the price, heh.

Did you have/use this book at some point? Or was it just one that looked good when you searched?
by TheWaterBear
Sat Nov 14, 2009 7:08 pm UTC
Forum: Mathematics
Topic: PDE Solution Methods
Replies: 9
Views: 1534

PDE Solution Methods

In my nuclear analysis class, we just got into partial differential equation solution methods, and I was hoping someone might be able to suggest a good book on the subject.

If it would influence your suggestion, we are dealing with mostly 2-D problems, in things like heat conduction.
by TheWaterBear
Wed Nov 04, 2009 11:59 am UTC
Forum: Mathematics
Topic: A little perspective, if you please
Replies: 9
Views: 1715

Re: A little perspective, if you please

MidsizeBlowfish wrote: (A B should never be a problem in college...it's a damn fine grade.)


I think I might have to finally get used to that sentiment this semester :/
by TheWaterBear
Sat Oct 31, 2009 3:14 pm UTC
Forum: Mathematics
Topic: Trig identity equations
Replies: 37
Views: 2550

Re: Trig identity equations

My teacher is adamant that you can't change either side to prove it, but it seems to me that to prove that 1-sin^2(x)=cos^2(x), you'd need to add sin^2(x) to both sides to make it a known identity. Why are you not allowed to do that? Just wanted to point out, you could rewrite 1 as cos^2(x) + sin^2...
by TheWaterBear
Fri Oct 30, 2009 9:18 am UTC
Forum: Mathematics
Topic: Differential equations homework
Replies: 4
Views: 685

Re: Differential equations homework

The Sticky-Note King wrote:So is the family of [imath]2x^2+8x+7[/imath] also {[imath]x^2,x,1[/imath]} because all the parts also fit in that family, or is a function with addition different? In that case, would the family be {[imath]x^2+x+1,x+1,1[/imath]}


I believe it is also {[imath]x^2,x,1[/imath]}.
by TheWaterBear
Thu Oct 29, 2009 9:43 pm UTC
Forum: Mathematics
Topic: Trig identity equations
Replies: 37
Views: 2550

Re: Trig identity equations

I had the same argument when I was taking trig. You can do it your way as long as you are careful. Basically, you have to make sure that whatever you are doing to both sides can also be undone by an inverse operation. Ie, if you want to prove A=B, its ok to do 2A=2B because you can undo that by mul...
by TheWaterBear
Thu Oct 29, 2009 9:22 pm UTC
Forum: Mathematics
Topic: Differential equations homework
Replies: 4
Views: 685

Re: Differential equations homework

y' + y = x ; y(0) = 1 You can use an integrating factor to solve this problem. If you don't recall how to do this, check out wikipedia: http://en.wikipedia.org/wiki/Integrating_factor y'' + 3y' + 2y = 2x^2 + 8x + 7 ; y(0) = y'(0) = 0 This one is a little ...

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