Survey posted 2003-06-06 23:32 by Henrik.

Contribute ideas to surveys by sending a mail to survey@ticalc.org.

Survey contributed by Eduardo Corpeņo.

This is something I've often thought about, actually... and the answer is no. I'm not that good with 3D graphing. I have honestly tried many times, though.
So... what IS the equation? ;-) I assume it has something to do with sine/cosine because there's a wave going through, but I can't get it to be circular like that.

Well, because the waves seem to get smaller, you also know there is going to be some kind of division by a positive value, and also, what is the equation of a circle? to get the circular part you have the main part of the equation be "sqrt(x^2+y^2)" This should help somewhat....or you can just look at all the equations that were posted before this one....

YYYAAAYYY!!!... they finally posted my survey!

I tried graphing it twice: The first time I came up with a function that's not quite the one in the logo. The second time, I came to a much better one.

After studying telecomunications, I realized that it looks like a rotated y(x)=sin(x)/(x) sort of function. So I thought of rotating it by expressing the function as a z(x,y) function (3D), and sending the 2D circumference formula as the parameter.
Like this:

y1(x) = when(x=0,1,sin(x)/x)
z1(x,y) = y1(sqrt[x^2+y^2])

The 2D function should be 1 for x=0, since we all know that sin(0)/0 is not defined.

Sorry to be the bearer of bad news, but I plugged that in and I didn't get the circular graph. However, I did get the "ripple" portrayed in the logo, but it was circular. Instead, it was "rectangular". Instead of having a large "hump" in the middle of the graph, circumscribed by an uplifted "ring", I got what looked like a cross-section of the curve, but in 3D. Use this equation and you'll see what I mean:

z1(x,y) = (when(x=0,1,sin(x)/(x))(sqrt(x^2+y^2))

I would have done it you're way, but I got nothing at all when I tried it (in both radians and degrees).

uhhhh... maybe bad news for you... I DO get it right... there must be something wrong with your window parameters... here are mine:

Coordinates:Rect
Radian angles

eye theta: 54 eye fi: 48 eye psi: 0
xmin: -12 xmax: 12 xgrid: 23
ymin: -12 ymax: 12 ygrid: 23
zmin: -0.2172 zmax: 0.94 ncontour: 5

the equation you wrote is wrong... i mean, it's not the same i specified... your function doesn't do anything when y=0.... That's why there's an empty plane at (x,0,z)
besides, it multiplies sqrt(x^2+y^2) to the whole "when" statement, which accomplishes... uhhh... something else :P

z1(x,y) = (when(x=0,1,sin(x)/(x))(sqrt(x^2+y^2)) This is wrong


I don't think you understood quite well what i meant: you have to define TWO different functions, one in 2D, and one in 3D:

y1(x) = when(x=0,1,sin(x)/x) (set Graph mode to Function)
z1(x,y) = y1(sqrt(x^2+y^2)) (set Graph mode to 3D, and SELECT z1)

you have to invoke y1 inside z... get it?

i like defining two functions because this way, the concept of rotation stays clear (to me, at least)... you may also define just one 3D function, but it looks all fuzzy (again: to me):

z1(x,y) = when(x=0 and y=0 ,1,sin(sqrt(x^2+y^2))/sqrt(x^2+y^2))

i hope this helps ;)

Yes...I did exactly that the first time (by defining y1 and using it in the z1 equation), and I got a flat plane with a whole in the center. I'll try adding the window ranges, though...I used the standard window ranges when I tried your method.

I also e-mailed TI and requested the equation. I'll post it when (if) they reply.

*hole

Grow Up! That little list says don't flame people and don't use language, and *hole implies language.

...
He was correcting the spelling from "whole" to "hole" IN HIS OWN POST. *rolls eyes*

And your flaming.

Now that I know what falming is, what is trolling?

-W_

Apparantly trolling is making a comment that encourages other people to flame and create a huge arguement.....
Or, was that a sarcastic question. I only found out what trolling was last night (If I am wrong please tell me).

So, that would make me a troller. Though I have stopped, I was at one time. How interesting.

-W-

no, that makes you a troll.

Wait. If it makes me <u><b>A</b></u> troll, then I am not trolling. you cannot have it both ways. it is either an adj, and describes, or a verb, that tells what I do. if I am trolling, then I am one who trools, thus, a troler. If I am a troll, then I am not trolling. I hope this makes sence, it is 3:55, my time, and I am trying to get a point across. Please correct me, if I am wrong, or you want to yell.

-W-

Sorry, it was late, and i messed up. It is used as a derict object. But still, My complaint still stands.

-W-

"Please correct me, if I am wrong, or you want to yell."

That is considered trolling.

Anyways, adjective and verb use can sometimes be confusing, so I will attempt to explain. Some words work in a lot of ways. For example: Troll: Noun. Troll: Verb. Trolling is something you do, but it can also be used as an adjective, as in, "The trolling calculator programmer."

Okay... Now I made myself confused.

Calling someone a "Trol" could be classed as flaming, then again it could be also 'trolling'. How about you just use the word "provoke"? OR DON'T YOU KNOW THAT WORD? ;-P (jk)
....but seriously?

That sounds right to me...

Troll-someone who floods boards with randomness (which can actually be fun to read, sometimes)
Flame-A verbal attack on somebody through chat/message boards/etc.

The * implies a correction or a third person action.
An * in front of a word means it is a correction.
Words(s) surrounded by *'s implies an action.
*rolles eyes*

*rolls

LOL... good example. :) *laughes*

*laughs

I thought he meant a hole in the graph at (x,0,y).

OMG, it was his OWN POST that he corrected! SHEESH!

Why would you complain about someone correcting their own post? *rolls eyes some more*

Ow... my eyes hurt from too much rolling.

It looks close, but it's not quite it...the central tower-like-thing is crooked in that equation...

yeah... like i said, it's my best guess... i was thinking that a rotated raised cosine-pulse would be a better guess, since you can manipulate it's parameters for controlling it's shape.

Umm... there's an extra "(" before "when(", just to tell you.

What's sqrt? And I'm not exactly the greatest at 3D graphing so if you can show what you have to input exactly step by step that would be great.

"sqrt" means "Square Root"... we use "sqrt" since there's no *standard* ASCII character for it's symbol...

in your calc, you have to use the proper square root character: [2nd]+[Multiplication sign]

for instructions, refer to my reply to the post named "YAY!!!...um...no" before this one

I think there is one in DOS, though... Alt 252, but I'm not sure...

Anyway, I use sqrt() too. Or SQR() (from QB)

ehh... the site doesn't use ascii...

every site uses ascii its the transmition of a binary number into a character.

every site uses ascii its the transmition of a binary number into a character.

You posted that three times?

No, thats weird it did it by itself i dont know why

Well, you probably just pressed "Post" three times. Instead of doing that, you could just be patient. (If that offended anyone, sorry)

every site uses ascii its the transmition of a binary number into a character.

Well you shouldn't rule out UNICODE or any other DBCSs...so I would say that no they do not necessarily use ascii. It all depends on what encoding you have selected for your browser really. Different code pages map to different glyphs. ASCII is too outdated and single sided for the internet age.

Hey, at least it works. Some of these new things don't.

Um, is your name supposed to have three t's in it?

You can see the equation at technoplaza.net > cool graphs > 3d graphs. It's nr. 3.

Equation: cos(sqrt(x^2 + y^2) - 0.04 * PI) / sqrt(x^2 + y^2)

i cant do that. I dont have a 89 or 92. yet

i cant do that. I dont have a 89 or 92. yet

i cant do that. I dont have a 89 or 92. yet

We "heard" you the first time :)

LOL, that's the second time on this board that somebody posted something three times... It was tempting to do it was this message, but that would be a little too annoying ;-)

Hey, are there programs that can "read" a webpage or some other text to you? That would be interesting...

Yes. In fact, one's built in into Windows XP. Just go to Start > All Programs > Accesories > Accesibility > Narrator. It reads the text under your cursor. But it can be confusing, as in:

Computer: Hello, this is the narrat-
*You accidentally move mouse a little bit*
Computer: Hello, this is-
*You accidentally move mouse again*
Computer: Hel-
*You accidentally move mouse yet again*
Computer: H-
*You get annoyed and turn off Narrator*

And, like I said earlier, people who post more than once just pushed the "Post" button too many times. Maybe they were too impatient. Maybe they pushed it for emphasis. Maybe, after waiting for a while, they thought they didn't push it, and pushed it again. Maybe MV's conspiracizing against Magnus. Although I doubt that.

The three post reply is something strange.
It happens from time to time and it happens a few times at once. I know it can be caused by something out of your control because it has happened to nearly ever post once, and I definitly only hit the button once.

In answer to the other question. YES, there are various browsers for the blind. I don't think many of them are free, but they do exist.

I need to see that XP Narrorator thing... does it read stuff like 13375p34k?

"4ll j00r 8453 4r3 83l0n9 70 u5"

or just jibberish?

lasfjlasdkfjasldfkjasdlfk

Can it read HTML?

<b>read this</B>

LOL... I need to see this :) Err... hear this.

You don't actually need an 89/92(+). I don't remember where exactly (check there archives), but I found an app for the 83+ that allows for 3D graphing. It's pretty acurate too.

I did that and got a flat plane with a hole through it.

I used an 83+ with the Graph^3 App

Nick_S

Use radians.

hey henrik, instead of posting who contributed the surveys everytime, why not make a little script that automatically displays it?

Because this way no one can brag about FIRST POST! It's a win-win situation.

but maybe no_one can brag about it

What the heck?

If I do get the first post, I'd write something worth reading other than just "First Post!"

I Agree, It Should be something that someone wants to hear

They could always brag second, if they were to brag first...

But, the script thing that RCT suggested, IMO, would be nice... you could have a little note at the bottom of the survey in small text that says "Contributor: <name>"