[CRASH] plotfunc() fails

[alexzkter]

I'm trying to get all answers from a Van Der Waals cubic equation.

Here's the definition of variables:

I defined 'x' too (x:=0)

When trying to plot the following equation on CAS, the hourglass stays there forever.


Which doesn't happen on it's equivalent form, the standard cubic form:




Anyway, I just managed to get all 3 answers from both forms of my equation.
There are 4 ways to solve the equation, by using the following sintaxis:

• With solve
  solve(equation,var)
  solve({equation},{var}) For multiple equations.
  

• With fsolve
  fsolve(equation,var)
  fsolve([equation],[var])--> For multiple equations, but this one only shows 1 result in my case.
  

[parisse]

Can you write your equations in plain text instead of a screenshot?
Like this
P:=7000000.; R:=8.314; T:=423.15; Tc:=369.8; Pc:=41.9*101325;
a:=27*R^2*Tc^2/64/Pc; b:=R*Tc/8/Pc;
plotfunc(R*T/(x-b)-a/x^2-P)
It's much more efficient, because anyone can check quickly by doing a copy/paste, and you are certain we check with the right data.
I just checked on the emulator, it works.

[alexzkter]

(06-22-2014 05:54 AM)parisse Wrote:  Can you write your equations in plain text instead of a screenshot?
Like this
P:=7000000.; R:=8.314; T:=423.15; Tc:=369.8; Pc:=41.9*101325;
a:=27*R^2*Tc^2/64/Pc; b:=R*Tc/8/Pc;
plotfunc(R*T/(x-b)-a/x^2-P)
It's much more efficient, because anyone can check quickly by doing a copy/paste, and you are certain we check with the right data.
I just checked on the emulator, it works.

Yes, I'll do that next time.
I typed in plotfunc(R*T/(x-b)-a/x^2-P) on a note, copy-pasted it on CAS and I still get the hourglass. Even if a and b are declared as you did.

[parisse]

If it does not work on your version of the emulator, and it works on mine, then it probably means some bug has been fixed.

[alexzkter]

(06-22-2014 02:35 PM)parisse Wrote:  If it does not work on your version of the emulator, and it works on mine, then it probably means some bug has been fixed.

I have the latest Rev.6031 ...