HP Forums

In CAS I can invoke Toolbox > Algebra > Factor as follows:

factor(x^4 - 1) --> (x-1)*(x+1)*(x^2+1)

So far so good. Now, if I store 2 into variable "x" and invoke factor again we have

factor(x^4 - 1) --> 15

In other words, if I have used a variable I can no longer obtain symbolic results with that variable. How do I mark a variable unused so it can be used for symbolic calculations?

I don't own PRIME, but in HP world 'Purge' is what is seems to be often used to get rid of variables. Here is one google result with Purge, HP Prime and some other words I did throw in

http://www.hpmuseum.org/cgi-sys/cgiwrap/...ead=254251

If this is not what you were after ask more.

if you want to clear the cas back to "Default", you can run the command "restart". Note this will wipe all cas variables and reset everything CAS related.

purge(x) will delete that one item by name. You can also press the VARS key, tap on "CAS", then find your x in the chooser and press the BKSP key. That will delete it through the UI.

(11-05-2015 04:49 PM)epp Wrote: [ -> ]How do I mark a variable unused so it can be used for symbolic calculations?

Instead of purging it, you can also enclose the expression in single quotes, which prevents the variables from being evaluated. Follow this history from the top down, noticing the single quote marks in one of the inputs: