Plotting CAS expressions with the Function App [SOLVED]
05-01-2016, 10:20 AM (This post was last modified: 10-23-2016 09:07 AM by JMB.)
Post: #1
 JMB Member Posts: 98 Joined: Jan 2016
Plotting CAS expressions with the Function App [SOLVED]
Using the ilapalce command in CAS, I have obtained an expression in the variable t.

Now I want to plot this function using the Function App, so I run the App and import the CAS expression pressing the Menu key and selecting Get from CAS. Then, before pressing Ok I have to manually substitute X for t all over the expression, because X is the only variable name accepted by the Function App.

What I'd like to knows is if there is an easer way to substitute X for t in CAS before switching to the Function App, or inside the Function App.

The command subst(expression, t=X) does not work because X is a real variable with default value 0.
05-01-2016, 11:31 AM (This post was last modified: 05-01-2016 11:38 AM by cdecastro.)
Post: #2
 cdecastro Junior Member Posts: 22 Joined: Dec 2013
RE: Plotting CAS expressions with the Function App
In CAS mode, take the expression you get and store it in F1(x) with the lower case x. The entire expression will be translated to one in terms of X in the Function window (Home mode). The Home/CAS disconnect continually frustrates me. I understand that we have do disjoint systems (developed essentially independently) that do not interact seemlessly - but I sure wish they did. Hope this helps.

Chris

P.S. #1 - I did not address the t to x conversion. Just use subst(expression, t=x) then store the result.

P.S. #2 - You don't need to perform the substitution, you can just use t and the t to x conversion will be made automatically. (e.g. w+1 -> F1(w) will be translated and stored as x + 1 -> F1(x)
05-01-2016, 01:12 PM (This post was last modified: 05-01-2016 01:13 PM by JMB.)
Post: #3
 JMB Member Posts: 98 Joined: Jan 2016
RE: Plotting CAS expressions with the Function App
Thanks Chris, that's exactly the kind of automatic substitution that I was looking for.

Josep.
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