/sci/ - Science & Math

>>5960530
SQ1:
I do not think that the evaluation of an anti-derivative at a point has any intrinsic meaning.

In many fields of science and engineering, the anti-derivative of some function has meaning, though.

the integral has a meaning over a range, whereas the derivative has a meaning around a point, big difference here;

As you can define a derivative as a function, so that you can evaluate it at any point, you can use the indefinite integral to evaluate an integral over any range.

SQ2:
Beware your notations:
the vector won't tend toward the largest eigenvector (there is no "largest eigenvector", since twice that vector could be "larger").
I think you mean "towards an eigenvector associated to the largest eigenvalue" (in modulus)".
That is still false; the components will still keep growing or getting small (depend if the eigenvalues are <1 or >1).
But the ANGLE of the iteration with the eigenspace corresponding to the biggest eigenvalue will diminish, yes.

SQ3:
Aerials have to detect variations in space of the wave, so they have to be bigger than only a fraction of a wavelength.
However, if they are too big, the induced electrons movement will be averaged over the length of the aerial... Depriving it from actually doing what it was built for: detect waves and their forms.
So you have to compromize: aerial size ~ wavelength

Diffraction occurs when slit size is ~ wavelength because heisenberg's incertainty principle:
photons that go through the slit have a pretty determined position: dz is small
but as dz*dp_z is minored, it means that dp_z get bigger the more dz is small.
When dz is ~wavelength, dp_z starts to take unnegligible proportions, thus the visible effects of diffraction. (diffraction always occurs, it's not always detectable).

>>5960579

Yes, what you said is what I think I was getting at. So, the angle between the vector and the eigenvector associated with largest eigenvalue will diminish. Can I change my square matrix to diminish the angle between the vector and one of the other eigenvectors? Could I rotate the the square matrix such that the 'largest' eigenvector is orthogonal to the vector being operated on?

>>5960628
my first reflex when reading "orthigonal" is "take the transpose".
See what it gives you, I'm too tired to try myself!

Brace yourselves everyone, for full force stupid.
When do you use calculus in physics for reasons other than derivation?
And before you ask, no I have not taken a physics course beyond babby HS physics (yet).

>>5960677
Remember how in physics you use displacement now (a triangle ?) well when you learn about limits you can do some calculus and make that displacement infinitesimally small, and mark it as d.

This allows you to get an exact value of a function at any given time for example let's say someone drives his bike down a hill. You want to know his exact speed at 5 seconds (his speed is changing with a given function), you will be able to get it using derivatives, before you couldn't.

>>5960687
Or for example you can now have velocity as a function and you can integrate the velocity function over the x axis (which is time for example) to get distance, before calculus you couldn't do this if the velocity was not a linear function.

These questions aren't stupid enough.

>>5960719
Sorry.
What is a vector exactly?

>>5960733
pfffff it's an arrow obviously. What are you, twelve?

>>5960628
I really don't see a way, sort of "computing" the largest eigenvalue eigenvector with this algorithm, removing the largest eigenvalue numerically (see what I mean, so that its eigenvalue is 0), then restarting the algorithm, and so on until you get all the eigenvectors.

I don't much of a point to it though, it'll be painstakingly slow as an algorithm. I'm curious, why would you want to do that?

>>5960733
An element of a vector space, duh.

>>5960687
>>5960690
What about in areas other than kinematics? I know that force is the derivative of momentum with respect to time, but how do you use that when you work with scalar quantities most of the time?

>>5960530
SQ3:2 electron position is a probability. Put differently, it really is in two places at once. Put even ore differently, an electron in front of you is also behind you and on the other side of the moon. Add all these probabilities together and you have zero point energy. It's big, but you cannot get anything out of it since there is no defined lower energy to drain it to.

>>5960755
>but how do you use that when you work with scalar quantities most of the time?
Take the derivative of the scalar function?

>>5960767

>there is no defined lower energy to drain it to.

Could you pump it? a la refrigeration or population inversation in a laser.

>>5960779
>inversation
inversion

>>5960751

I don't know why.

>>5960782
>Take the derivative of the scalar function?
But that's ze-
...
...
oh

Dont know if its more /g/ related but it has the word science in it.
I dont know much about CS but want to get started, dont know if i should learn a programming language or what. Where do I begin?

>>5960819
This is a thread for stupid questions, not for things that can be googled.

But yeah, learn a language as it's the tool you'll be using then buy a CS text book or go to University or something.

http://cli.learncodethehardway.org/book/
http://learnpythonthehardway.org/book/

>>5960819

Learn the easiest.

>>5960828
>This is a thread for stupid questions, not for things that can be googled.
aka stupid questions

>>5960819
I learned with a scripting language first: Maple.
In the end it doesn't really matter which one you pick.

>>5960853

What have you learned in addition to Maple and do you still use it?

>>5960819
I have a degree in computer science and know a ton of languages. Ages ago "logo" was used to teach kids but it was otherwise useless. Having given this considerable thought here is my suggestion:
1) Learn HTML
Note HTML is not a programming language, it has no conditionals (if foo then bar), but it introduces you to the concept that some stuff is displayed like in a typewriter and some stuff is control.
Then learn javascript. It has conditionals. You can even write entire graphics games in it, but learn important modern concepts: classes, arrays, loops, events, and it costs....
NOTHING!
You have a computer to browse 4chan, you can learn and run html/javascript without purchasing any software.

This is a spartan site but I like short simple explanations and tons of interactivity. It is the the go to site for learning web programming.
http://www.w3schools.com/

It's how I learned javascript. I even wrote some games. Keep it fun, though, and make time for it so you can enjoy it.

>>5960863
I learned Maple first. I don't use it very often because I don't need to do very complex formal calculations.
Then I learned CAML because it's meant to be a teaching language and it was part of my cursus.
Then I don't remember in which order, I learned Java and C++ and Fortran.

Nowadays I use mostly Fortran.

Really once you know how to program learning another language is just a matter of a bit of syntax and maybe learning some fancy new concept like pointers or object-oriented programming.

>>5960877

Why does /g/ lose its sides whenever fortran is mentioned?

>>5960884
Well they don't do any scientific calculation.
And yeah, I wouldn't use Fortran outside of my heavy-load calculations. Like, making a commercial software with an UI and everything in Fortran has to be a nightmare.

>>5960530
>What is the meaning of the indefinite integral

It's the family of all function with the same derivative

>Repeatedly operating on a vector with a square matrix will cause the vector to tend toward the largest eigenvector. Is that right? How do I tend a vector toward one of the other eigenvectors?

No, it will tend to the eigenvector with largest eigenvalue that is a component with respect to projection of the vector onto the eigenspace of the matrix

Stupid questions need stupid answers.
Stupid answer number one (SA1):
It means you gots to remember the "+C" or you loose a point on your test answer!

SA2: You can operate with the inverse of the square matrix. Of course if it's a rotation matrix, yada yada yada. Q.E.D.

SA3: Uh, you sure about that? See Beverage and rhombic antennas, waveguide antennas, inductive and capacitively loaded antennas and DF loop antennas, for examples.

That pick is the worst AM detector I ever did saw.

Here is a stupid question:
0.142857(142857). . . * 0.076923(076923) . . . = 0.010989(010989). . .
Why don't more numbers repeat in the answer?

Here is a stupid question:
0.142857(142857). . . * 0.076923(076923) . . . = 0.010989(010989). . .
1/7, 1/13
Why don't more digits repeat in the answer?

>>5960819
I don't know if it is still available, but ftp.microsoft.com used to have the old Windows 95 version of QuickBasic, QBASIC.EXE and QBASIC.HLP, available for download. It's an interpretor limited in size and speed but it is really simple and has line by line syntax checking. For more power and speed, the Freebasic Foundation has a free compiler that will compile the QBASIC code (/qb option). I wish there was a free Fortran foundation.

>>5960877
salut taupin

>>5960755
Or for example I remember a problem where a fish tank was under water and I had to calculate the pressure on the front of it.

You need calculus there because each point of the tank is at a different distance under water meaning the pressure is a bit different at every point of it, so you have to integrate over it to get the pressure.

>>5961200
>worst AM detector

I maed you a better one

>>5960677

Mechanics essentially is just methods of derivation. The whole purpose is to derive explicit equations of motion from some fundamental law, which are themselves calculus "statements" describing the behavior of the system implicitly (eg Newton's law is a second order differential equation).

>>5960530
The indefinite integral is a function that measures the change in something since time 0. If f(x) models gal/score, F(x) would tell you how many gallons have been added or removed from the tub since t=0

>>5960745
what are you, math ignorant?

>>5961260
Because the repeating sequence is the same. Haven't seen that notation before.