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By default, when I plot a graph, the axis seems to be at the lower limit

x=linspace(-10,10,20) y=4*x+2 plot(x,y) 

http://is.gd/f9zOkl

How can I have the axis when x=0 & y=0, for example below

http://www.regentsprep.org/Regents/math/algtrig/ATP8b/inversegraph.gif

UPDATE

If its not possible to use real "axis", I am thinking of plotting the graphs x=0 & y=0 for the y & x axis respectively, how might I do that?

Then isit possble to show where they intersect? like in format like (x, y) eg. (0, 2)

3 Answers 3

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After creating your plot, you could try this which draws lines:

% Keep the current graph hold; % Draw X axis plot([-6 6], [0 0], 'k-'); % Draws a line between x=(-6 to 6) and y=(0 to 0) % Draw Y axis plot([0 0], [-5 5], 'k-'); % Draws a line between x=(0 to 0) and y=(-5 to 5) 

In plot([-6 6], [0 0], 'k-'); replace -6 with the lower limit for x and 6 with the upper limit.

In plot([0 0], [-5 5], 'k-'); replace -5 with the lower limit for y and 5 with the upper limit.

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try this:

set (gca, "xaxislocation", "zero");

set (gca, "yaxislocation", "zero");

It works only for Octave, not Matlab. Would be interesting also to know how do this with matlab.

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    I have seen this command in many of the sites but surprisingly it doesn't work in my GNU Octave2018-09-02
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It seems that this is not (easily) possible. For your information: I found the following links:

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    Thanks, I am trying to plot graphs of x=0 and y=0 to simulate the y & x axis, how might I do that? See updated post/question2011-08-28