Piecewise defined discontinuous functions in Mathematica

Anyone know how to graph a piecewise defined discontinuous function in Mathematica so that the discontinuities actually show up?


I googled and found a solution here but it doesn't work. I've been editing the graphs with microsoft paint to make them look discontinuous but it is very time consuming, especially since I need to create so many graphs.

Anyone have any experience with this?

Did you try what was shown in that document at the bottom of page 9?

Quote:

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In order to create a discontinuous graph, plot the portions separately and then combine using the Show command.

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Yup it errors out:(

I remember that document also saying something about errors because of the domain being used for a particular function. Show us the function along with the command you are using to plot it.

I tried to plot the same one they had there and it didn't work.

Excatly what do you mean by "discontinuities actually show up"?

I barely know any Mathematica but I just did this:

Code:

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p1 := Plot[ x , {x, -1, 1}];
p2 := Plot[x + 2, {x, 1, 3}];
Show[p1, p2];

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In the last plot a discontinuous function is shown. To me, the discontinuity is clearly shown.

Thank you!:)

For some reason when I used the code in that pdf it did not work. Next time I should try rereading about the show function in the documentation.

I still have to edit the graphs though because I want to indicate whether there is a hole in the graph at a certain point but that is no big deal I guess.