Knowledge Base/Using the Desmos graphing calculator/User Guide Topics

Restrictions (piecewise)

Team Desmos
posted this on November 21, 2012 19:23

To limit the domain or range (x or y values of a graph), you can add the restriction to the end of your equation in curly brackets {}. For example, y=2x{x>0} would graph the line y=2x for x values greater than 0.

To try it out in Desmos, click the Restrictions Tour in the help menu:

Screen_Shot_2013-12-29_at_9.31.26_PM.png

 

 

Comments

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Brendon Hackett

that is very helpful, can you show us how to do a step peicewise?

December 12, 2013 11:46
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Fabrice Neyret

More:

- you can cumulate conditions:    y = sin ( x/a )   { a > 0 } { 0 <= x <= a*pi }

- for parametrics curve, the condition must be *in* the parenthesis:  ( t,  sin ( t/a )   { a > 0 }  )

- you can also use the  "if elseif else" version :  y = { a <= 0 : 0 ,   0 <= x <= a*pi  : sin ( x/a )  , 0 )

  with any number of cond : expression terms, and the default (final) expression is not mandatory

January 08, 2014 21:28
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Alexandre Gurchumelia

It's missing the very important part, making piecewise function in single line, so that when you differentiate it or use it in any why elsewhere, the function remains whole. Syntax is:

F(x)={x≤0 : x², 0<x<π/2 : 2x/π, x≥π/2 : sin(x)}

Now it's usable in any situation, for instance:
https://www.desmos.com/calculator/y9bbgn6ul9

June 21, 2014 07:00
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Tom De Vries

yes,  I was sad about this too,  had some previously produced graphs that are now broken, though I respect the fact that some other things are much easier.  

How would you create a piecewise function in one line.   Not just for differentiation, but also to illustrate transformations as in this (previously working)  example

https://www.desmos.com/calculator/ou6w7lmnim

 

August 19, 2014 04:19