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

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this is OT but I think it could help the gerneral user somewhat. I think it is safe to asy that someone checks the news items and the replies to them based on whether or not they have read the news yet and if there are any new posts. Well, it would be beneficial if the same "comment counter" could be added to the bottom of the survey under the "Results" and "Vote" buttons.

I feel the same way, could this be done? That would be great... I do the exact same thing.

I was gonna mention this, but i've been too lazy.

I think that someone (maybe it was Michael O'Brien again, or it might have been you) mentioned it a few months ago. They should have that right beside the contributor of the survey! ;-)

I think it was RCT because I can't remember doing that. But If someone did say anything about it I'm pretty sure I would have endorsed it.

yes, since i have all the good ideas around here. :-p

Uh, like your subject?

LOL

Yeh, they are lovely birds are't they, such beautiful colours on their feathers.

LOL ;-)

Does anybody think it could be possible that it was drawn in by hand using the pen?

I guess, but if they did, then they had more time on their hands than I do, which isn't possible. ;-)

It looks like a 3D graph, anyway. If someone could just do that with pen, then I would have to go hunt them down.

It's the same image that TI has of the 89 on their site.

Maybe ticalc stole it from THEM! LOL... Mulanda made it with pen :)

No. It would be much quicker and easier to do by machine. It should be a relatively simple graph - you just need to know what it is.

I e-mailed TI for the equation, and this is how they replied:

Jude,

Thank you for contacting Texas Instruments, an educational technology
company.

The equation for the 3D graph found on the TI-89 is:

20*cos((x^2 +y^2)/4)
z(x,y) = -------------------------------
(x^2 +y^2 + pi)

WINDOW:
eyetheta = 20
eyephi = 70
xmin = -5
xmax = 5
xgrid = 20
ymin = -5
ymax = 5
ygrid = 20
zmin = -1.2953 (approx)
zmax = 6.3662 (approx)
zscl = 1

Hint: The calculator has to be in Radian mode.

Regards,

Yowanda Brooks


Hope this helps :)

Boy, that's a mouthful. I can't tell cause of the font, but I'm assuming that's a fraction with the top part being a numerator and the bottom part being the denominator. Also, I know absolutely zilch about 3D graphing. What is eyetheta and eyephi?

eyetheta and eyephi are two variables, if you want to calll them that, that are used to view the graph at different angles relative to a separate axis.

Really beats me on what eyephi is supposed to look like, but I asked TI before this poll, and i got the EXACT same email you did JcN!

It's probably an auto-response e-mail.

or they copy and paste that stuff.

A lot of people probably e-mailed them after seeing this poll... LOL

Okay, I know the equation looks a bit odd in this text (because of the font differences), so here it is:

z1(x,y) = (20*cos((x^2+y^2)/4)/(x^2+y^2+pi)

You actually need to tinker with the zmin and zmax variables to make the "hump" in the center look taller. Apparently, that is the equation used, even though it (at first) doesn't look like the logo when graphed.

any ideas on how to graph this with Graph³ for TI-83 Plus? I just get a hill with no "waves" :(

Use the equation mentioned above, but make sure that your calc is in radians. Set the window factors like this:

xmin = -6
xmax = 6
ymin = -6
ymax = 6
zmin = -1.2953
zmax = 6.3662

That should produce a graph similar to the logo, but because of the limitations of the TI-83+ pixel density, the graph will look more vague and "choppy".

you do get the "waves" but the 83+ chops it off right as the "waves" start.
Try viewing it at different angles-You'll see what I mean

Nick_S

"Now where's my beans?!",0