# 3D plot a linear function y=a\*x for undefined constant "a"?

**URL:** <https://community.wolfram.com/t/3d-plot-a-linear-function-y-a-x-for-undefined-constant-a/9286>\
**Category:** Questions\
**Tags:** graphics-and-visualization\
**Created:** [September 22, 2016, 12:53pm UTC](https://community.wolfram.com/t/3d-plot-a-linear-function-y-a-x-for-undefined-constant-a/9286 "2016-09-22T12:53:37Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![efdora](https://avatars.discourse-cdn.com/v4/letter/e/da6949/32.png) [@efdora](https://community.wolfram.com/u/efdora)\
**Post date:** [September 22, 2016, 12:53pm UTC](https://community.wolfram.com/t/3d-plot-a-linear-function-y-a-x-for-undefined-constant-a/9286/1 "2016-09-22T12:53:37Z")

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Hello! How can I get a 3D plot of the y=a\*x function for every possible value of ‘a’, where ‘a’ is a real constant? Something like taking the 3D graphs of y=0.3x, y=x, y=2x, y=7x etc and adding them all together in one graph. Thank you

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<div class="post-metadata">

**Author:** ![mthiel](https://yyz1.discourse-cdn.com/wolfram/user_avatar/community.wolfram.com/mthiel/32/42877_2.png) [@mthiel](https://community.wolfram.com/u/mthiel)\
**Post date:** [September 22, 2016, 1:18pm UTC](https://community.wolfram.com/t/3d-plot-a-linear-function-y-a-x-for-undefined-constant-a/9286/2 "2016-09-22T13:18:57Z")

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Hi Dora,

I am quite sure that I misunderstand your question, because it looks to me as if you need:

```
Plot3D[a x, {x, -2, 2}, {a, 0, 10}]

```

 ![ScreenShot2016-09-22at14.07.30.png](https://global.discourse-cdn.com/wolfram/original/3X/2/9/29fb58451b7796a8bb30ce6d93677d4e6539eac2.png)

If you only want the points you could use

```
ListPointPlot3D[Table[{x, a, a x}, {x, -2, 2, 0.1}, {a, 0, 10, 1}]]

```

 ![ScreenShot2016-09-22at14.14.36.png](https://global.discourse-cdn.com/wolfram/original/3X/2/3/232f6d32a50eda6c0b0c3cffa61a30fdce6f6255.png)

But all of this is very basic and is very well documented. So I suppose that your question has some gist that I don’t get. Could you explain this in more detail, please?

Cheers,

Marco