solve() problems

[C.Ret]

If you need only a rapid aperçu of the plot of your polynomial, you may use plotfunc(x²+x-1). You can easily have it full screen; touch the small plot figure and tap the (show) menu at the bottom of the screen.

If your polynomial expression is short enough, you can retape it into the Function App edit window.
But, if you are as lazy as me, an élégante solution consist in firth selecting the Function Application, then create a new program named CAS2FUN as a CAS function (don't forget to mark the case).

Code:

EXPORT CAS2FCN(Epr)                          // Returns CAS expression with lowercase x substituate by uppercase X
BEGIN
 EXPR( REPLACE("'"+STRING(Epr)+"'","x","X"))
END;

EXPORT CAS2FCN(Epr,n)                                 // Store substituated CAS expression as a regular plot function in slot Fn
BEGIN
 EVAL(EXPR(" ' F"+n+":= ' "+STRING(CAS2FCN(Epr))+" ' ' "));
 CHECK(n);
 n
END;

(Beware the position of single quote ' and double quote " Sehr wichtig !)


In the CAS window, you can copy any sophisticate exression as easily as the simplest by using this new CAS program :
Press [ToolBox]
Touch (USER) and select CAS2FUN in the list of User's program
Then select your polynomial expression in the display stack and touch (COPY) in the menu. This enter the expression of it as first argument of CAS2FUN
Then enter a number to designate the Function Application slot number to be used (from 1 to 9 or 0) and press [ENTER].

[attachment=9545]

The program convert your sophisticated expression by replacing lowercase x with uppercase X without evaluating it and store it in the F1 ... F0 slot of you chose ready to be plot !

[attachment=9544][attachment=9546]

La cerise sur la gâteau , you now have named your polynomials F1(x) and F2(x): so you can use these names to designate your polynomials to integrate, derivate or solve (or what ever you plan to do with these)
For example, in CAS windows: solve(F1(x)=F2(x),x) will return the list of the abscisses for all of the intersections : { -1.9308, 0.837,3.0938}