# Plot 2D Graphic Beginner Question **URL:** \ **Category:** Graphics and plotting\ **Created:** [November 26, 2023, 5:01pm UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259 "2023-11-26T17:01:45Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![scyscy](https://avatars.discourse-cdn.com/v4/letter/s/94ad74/32.png) [@scyscy](https://scilab.discourse.group/u/scyscy)\ **Post date:** [November 26, 2023, 5:01pm UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/1 "2023-11-26T17:01:45Z")
Can someone tell me please how do I plot 2D graphic of “y = x^2 + 2x + 1” with range of x = -10 to x = 10? Thank you ---
**Author:** ![mottelet](https://yyz2.discourse-cdn.com/free1/user_avatar/scilab.discourse.group/mottelet/32/13_2.png) [@mottelet](https://scilab.discourse.group/u/mottelet)\ **Post date:** [November 27, 2023, 8:03am UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/2 "2023-11-27T08:03:20Z")
Hello, You can have a look to the examples in the documentation at [plot - 2D plot](https://help.scilab.org/docs/2024.0.0/en_US/plot.html) ---
**Author:** ![scyscy](https://avatars.discourse-cdn.com/v4/letter/s/94ad74/32.png) [@scyscy](https://scilab.discourse.group/u/scyscy)\ **Post date:** [November 27, 2023, 9:07am UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/3 "2023-11-27T09:07:29Z")
Thank you so much for your reply. I still don’t understand when learning from the link you posted. I need to learn by example. Please anyone that could answer my question in my first post. ---
**Author:** ![onkanat](https://yyz2.discourse-cdn.com/free1/user_avatar/scilab.discourse.group/onkanat/32/269_2.png) [@onkanat](https://scilab.discourse.group/u/onkanat)\ **Post date:** [November 27, 2023, 11:42am UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/4 "2023-11-27T11:42:50Z")
```auto x = linspace(-10,10, 20); y = x.^2 + 2*x + 1; plot(x,y); ``` ---
**Author:** ![scyscy](https://avatars.discourse-cdn.com/v4/letter/s/94ad74/32.png) [@scyscy](https://scilab.discourse.group/u/scyscy)\ **Post date:** [November 27, 2023, 12:52pm UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/5 "2023-11-27T12:52:56Z")
Can you tell me please what “20” mean in “x = linspace(-10,10, 20);”? Thanks ---
**Author:** ![onkanat](https://yyz2.discourse-cdn.com/free1/user_avatar/scilab.discourse.group/onkanat/32/269_2.png) [@onkanat](https://scilab.discourse.group/u/onkanat)\ **Post date:** [November 27, 2023, 1:12pm UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/6 "2023-11-27T13:12:25Z")
shortly … linspace generates linearly spaced numbers between 2 reached bounds n integer number of requested values or columns. Default value: 100 Details in this [link](https://help.scilab.org/docs/2024.0.0/en_US/linspace.html) ---
**Author:** ![mottelet](https://yyz2.discourse-cdn.com/free1/user_avatar/scilab.discourse.group/mottelet/32/13_2.png) [@mottelet](https://scilab.discourse.group/u/mottelet)\ **Post date:** [November 27, 2023, 1:46pm UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/7 "2023-11-27T13:46:02Z")
Hello, Typing ```auto help linspace ``` should give you the explanation you asked for. S. ---
**Author:** ![scyscy](https://avatars.discourse-cdn.com/v4/letter/s/94ad74/32.png) [@scyscy](https://scilab.discourse.group/u/scyscy)\ **Post date:** [November 27, 2023, 2:48pm UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/8 "2023-11-27T14:48:52Z")
How do you display the graph like below pic? ![scil_graph_1](https://global.discourse-cdn.com/free1/uploads/utc/original/1X/80974dba3fe652c99f975f9532117cd531458eb5.png) ---
**Author:** ![mottelet](https://yyz2.discourse-cdn.com/free1/user_avatar/scilab.discourse.group/mottelet/32/13_2.png) [@mottelet](https://scilab.discourse.group/u/mottelet)\ **Post date:** [November 27, 2023, 2:52pm UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/9 "2023-11-27T14:52:48Z")
type: ```auto gca().y_location="origin" ``` if you have negative y values you can also add ```auto gca().x_location="origin" ``` ---
**Author:** ![scyscy](https://avatars.discourse-cdn.com/v4/letter/s/94ad74/32.png) [@scyscy](https://scilab.discourse.group/u/scyscy)\ **Post date:** [November 27, 2023, 2:58pm UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/10 "2023-11-27T14:58:21Z")
It says “invalid factor”. ---
**Author:** ![QwillDune](https://yyz2.discourse-cdn.com/free1/user_avatar/scilab.discourse.group/qwilldune/32/152_2.png) [@QwillDune](https://scilab.discourse.group/u/QwillDune)\ **Post date:** [November 27, 2023, 4:25pm UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/11 "2023-11-27T16:25:32Z")
Work’s fine here ![2023-11-27-09-24-54](https://global.discourse-cdn.com/free1/uploads/utc/original/1X/f5f9ad4945c2aae4d97f0b646fe1b810d229569f.png) ---
**Author:** ![scyscy](https://avatars.discourse-cdn.com/v4/letter/s/94ad74/32.png) [@scyscy](https://scilab.discourse.group/u/scyscy)\ **Post date:** [November 28, 2023, 9:38am UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/12 "2023-11-28T09:38:30Z")
I still have the error. What should I do? ![scil_error](https://global.discourse-cdn.com/free1/uploads/utc/original/1X/10317e46f028efb39e0e9a2e98f01a2ea67652ed.png) ---
**Author:** ![mottelet](https://yyz2.discourse-cdn.com/free1/user_avatar/scilab.discourse.group/mottelet/32/13_2.png) [@mottelet](https://scilab.discourse.group/u/mottelet)\ **Post date:** [November 28, 2023, 10:19am UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/16 "2023-11-28T10:19:05Z")
[scyscy](https://scilab.discourse.group/u/scyscy), please tell us which Scilab version you are using, and on which platform/OS. Thanks ---
**Author:** ![scyscy](https://avatars.discourse-cdn.com/v4/letter/s/94ad74/32.png) [@scyscy](https://scilab.discourse.group/u/scyscy)\ **Post date:** [November 28, 2023, 10:43am UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/17 "2023-11-28T10:43:53Z")
I am using Windows 10 and Scilab 5.5.0 ---
**Author:** ![mottelet](https://yyz2.discourse-cdn.com/free1/user_avatar/scilab.discourse.group/mottelet/32/13_2.png) [@mottelet](https://scilab.discourse.group/u/mottelet)\ **Post date:** [November 28, 2023, 10:50am UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/18 "2023-11-28T10:50:43Z")
Scilab 5.5.0 was released nine years ago and in this version recursive assignment was not possible. If you still want to use this version, you should write: ```auto a=gca(); a.y_location="origin" ``` or ```auto set(gca(), "y_location","origin") ``` If you don’t have any reason to still use this obsolete version, you should download and install the latest version ([Scilab 2024.0.0 | Scilab](https://www.scilab.org/download/scilab-2024.0.0) ). S. ---
**Author:** ![mottelet](https://yyz2.discourse-cdn.com/free1/user_avatar/scilab.discourse.group/mottelet/32/13_2.png) [@mottelet](https://scilab.discourse.group/u/mottelet)\ **Post date:** [November 29, 2023, 9:11am UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/20 "2023-11-29T09:11:10Z")
Hello, When I copy/paste this code into Scilab 6.1.1, 2023.0, 2023.1, and 2024.0 I get the expected plot without any error. S. ![Screenshot 2023-11-29 at 10.11.24](https://global.discourse-cdn.com/free1/uploads/utc/original/1X/8e8fbf1eb240d70d9d8e0c53689a3919318e8c98.png) ---
**Author:** ![scyscy](https://avatars.discourse-cdn.com/v4/letter/s/94ad74/32.png) [@scyscy](https://scilab.discourse.group/u/scyscy)\ **Post date:** [November 29, 2023, 10:50am UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/25 "2023-11-29T10:50:14Z")
How to show the -y axis? ---
**Author:** ![mottelet](https://yyz2.discourse-cdn.com/free1/user_avatar/scilab.discourse.group/mottelet/32/13_2.png) [@mottelet](https://scilab.discourse.group/u/mottelet)\ **Post date:** [November 29, 2023, 11:03am UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/26 "2023-11-29T11:03:56Z")
Hello, you have the answer here: > [@Plot 2D Graphic Beginner Question](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/9): > > type: gca().y\_location="origin" if you have negative y values you can also add gca().x\_location="origin" ---
**Author:** ![scyscy](https://avatars.discourse-cdn.com/v4/letter/s/94ad74/32.png) [@scyscy](https://scilab.discourse.group/u/scyscy)\ **Post date:** [November 29, 2023, 11:46am UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/27 "2023-11-29T11:46:06Z")
What about in scilab 5.5.0? I use below code but it doesn’t works: ```auto a=gca(); a.y_location="origin" ``` or ```auto set(gca(), "y_location","origin") ``` ---
**Author:** ![mottelet](https://yyz2.discourse-cdn.com/free1/user_avatar/scilab.discourse.group/mottelet/32/13_2.png) [@mottelet](https://scilab.discourse.group/u/mottelet)\ **Post date:** [November 29, 2023, 12:02pm UTC](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259/28 "2023-11-29T12:02:10Z")
If you don’t have negative x-data the y axis won’t show up, even after setting the y\_location Axes property. To force the axis display, you have to change the Axes limits, like in the following code: ```auto t=1:10; plot(t,sin(t)); a=gca(); a.x_location="origin"; a.y_location="origin"; a.box="off" a.data_bounds(1)=-1; ``` ![Screenshot 2023-11-29 at 13.01.28](https://global.discourse-cdn.com/free1/uploads/utc/original/1X/54331d67fa038aba9b23c78ef14efb369e2a4874.png) [Next page](https://scilab.discourse.group/t/plot-2d-graphic-beginner-question/259.md?page=2)