# Cool 3-D functions for graphing

#### LPHY

I am collecting nice 3-d functions to demonstrate graphing tool, if any one have great functions which will look great on 3-d plotting, please let me know.

Here are few equations I am using now. If you guys need I can provide a link to plot each of these graphs.

(01) x*y^3-y*x^3
(02) (x^2+3*y^2)*e^(-x^2-y^2)
(03) -x*y*e^(-x^2-y^2)
(04) -1/(x^2+y^2)
(05) cos(abs(x)+abs(y))
(06) cos(abs(x)+abs(y))*(abs(x)+abs(y))

Note:
I have discuss some 2-D functions for my earlier tool, which you can see on this thread
Cool 2-D functions for graphing

#### Office_Shredder

Staff Emeritus
Gold Member
You can probably find cooler functions if they're implicitly defined. Can your graphing tool handle those?

#### LPHY

Office_Shredder said:
You can probably find cooler functions if they're implicitly defined. Can your graphing tool handle those?
I am not sure what you looking for, here is one sample 3D graph drawn from the tool
Graph: cos(abs(x)+abs(y))*(abs(x)+abs(y))

#### LPHY

There was a bug, when some one put a function with spaces in middle, forums bbcode url not working, this is fixed now.

Homework Helper
How come Arildno didn't suggest to plot f(x, y) = 0 yet.. #### arildno

Homework Helper
Gold Member
Dearly Missed
How come Arildno didn't suggest to plot f(x, y) = 0 yet.. He is a lost case, so I resigned from trying to make him appreciate the beauty of the Great Annihilator.

I'll be back if he tries to top f(x,y,z)=0 in 4-D, though. Staff Emeritus
Gold Member

#### LPHY

Office_Shredder said:
I mean, for example, if I said to graph cos(z) + sin(xy - 2) = 0, could it graph that for z as a function of x and y?
Sorry you cannot graph this function

cos(z) + sin(xy - 2) = 0

function must be in this format

f(x,y)

where

f(x,y) = z

#### Office_Shredder

Staff Emeritus
Gold Member
1/(sin(abs(x)+x)-cos(abs(y)+y))

Last edited:

#### Office_Shredder

Staff Emeritus
Gold Member
LPHY said:
Its look great, let me try the link again
Graph: (floor(-e^(-x*y/1)*cos( (x^2+y^2)/10 ))+14*ln(10000/(x^2+y^2)+.01))*floor( cos(x^2+y^2)/10)+3*(ceil(x)-floor(x))*(ceil(y)-floor(y))

You are right, some thing wrong with the built in forums bbcode builder, when I copy and paste the URL, it is working fine. Probably a bug, may have to work on that to fix it for long formulas.

floor(e^(abs(x*y/2))+round(1/cos(x*y))) works out just as well, and doesn't look nearly so ugly from a function point of view :rofl:

Last edited:

#### robphy

Homework Helper
Gold Member
When I came up with my first function above, I was goofing around with various functional forms. When I came upon something I liked, I used it and didn't reduce it to a visually-similar but functionally-simpler form.

#### Office_Shredder

Staff Emeritus
Gold Member
robphy said:
When I came up with my first function above, I was goofing around with various functional forms. When I came upon something I liked, I used it and didn't reduce it to a visually-similar but functionally-simpler form.
I actually wasn't specifically trying to reduce your function, I just happened to stumble upon it (before looking at yours actually) #### Office_Shredder

Staff Emeritus
Gold Member
Did you change the program or something? Because 1/(sin(abs(x)+x)-cos(abs(y)+y)) is coming out differently now than it was before (specifically, part of it doesn't even show up)

#### LPHY

Didn’t do any changes to the program, did you try adjusting the Z-Axis boundary limit.

Try and see whether its work for you, if you are not sure the range you can set it to

z-min = Auto
Z-max = Auto

#### glab

Actually you can graph this...I tried it in grapher on my mac and it worked like a charm...

#### glab

Sorry you cannot graph this function

cos(z) + sin(xy - 2) = 0

function must be in this format

f(x,y)

where

f(x,y) = z
[QUOTE ]Actually you can graph this because grapher works with it...

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