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+--- Thread: [CRASH] plotfunc() fails (/thread-1678.html)
[CRASH] plotfunc() fails - alexzkter - 06-21-2014 05:01 PM
I'm trying to get all answers from a Van Der Waals cubic equation.
Here's the definition of variables:
![[Image: 2ibe1hk.png]](http://i62.tinypic.com/2ibe1hk.png)
I defined 'x' too (x:=0)
When trying to plot the following equation on CAS, the hourglass stays there forever.
![[Image: 33079rp.png]](http://i58.tinypic.com/33079rp.png)
Which doesn't happen on it's equivalent form, the standard cubic form:
![[Image: 2ivfi3t.png]](http://i61.tinypic.com/2ivfi3t.png)
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.
RE: [CRASH] plotfunc() fails - parisse - 06-22-2014 05:54 AM
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.
RE: [CRASH] plotfunc() fails - alexzkter - 06-22-2014 10:01 AM
(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.
RE: [CRASH] plotfunc() fails - parisse - 06-22-2014 02:35 PM
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.
RE: [CRASH] plotfunc() fails - alexzkter - 06-22-2014 06:11 PM
(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 ...
