Hi

I have a system of equations (4) which I would like to plot in regards to a fifth variable. Is there a good way to do this. Some of the solutions would end up as negative values, which is not an option I am interested in having.

C__A is my variable, and the other variables I would like to solve are tau,C__B,C__C,C__D. Im specifically interested in tau with regards to C__A. I hope this makes sense :)

regards

C__A := .75;
                              0.75

a := tau = (C__A0-C__A)/(-r__A);
                                  0.75                      
    tau = - ------------------------------------------------
                                              2             
            -0.00900 C__B + 0.03500000000 C__C  - 0.075 C__C
b := tau = (C__B0-C__B)/(-r__B);
                               2 - C__B              
          tau = - -----------------------------------
                                                    2
                  -0.00900 C__B + 0.03500000000 C__C 
c := tau = (C__C0-C__C)/(-r__C);
                                C__C                  
         tau = ---------------------------------------
                                        2             
               0.01800 C__B - 0.070 C__C  - 0.075 C__C
d := tau = (C__D0-C__D)/(-r__D);
                           13.33333333 C__D
                     tau = ----------------
                                 C__C      
sol := fsolve([a, b, c, d], {C__B = 1, C__C = .2, C__D = .2, tau = 50});

{C__B = 1.673672109, C__C = 0.2289836744, C__D = 0.4236721086, 

  tau = 24.66971264}

I have trouble solving this equation

fsolve(5000 = int(1/(0.1060444429e-1-0.2120888857e-1*X+0.1033933318e-1*X^2), X = 0 .. x), x)

It has a few points where the solution will go towards infinite, but that is not something that is an issue normally. I have no problems what so ever to solve this using my trusty TI-89, so Im wondering what needs to be done to actually solve this. I have tried giving an initial guess, and I have tried using solve, but it doesnt seem to do the trick.

Regards

Hi

I have a set of differential equations which I have solved for a specific value, and would like to use the second answer (F__A(V)) in my next calculations

What command can I use to retrieve that value?

sol(0.1e-4);
     [V = 0.00001, F__A(V) = HFloat(3.498873118476744e-6), 

       F__B(V) = HFloat(1.9101126881523255e-5), 

       F__C(V) = HFloat(9.550563440761627e-6)]
 

Regards

Hi

I have an ODE which is based on a seperate function, and I would like to make a plot with the information

dsolve([diff(X(W), W) = (0.536000000000000e-3*(1-X(W)))*(1+X(W)), X(0) = 0], numeric)

and

C_A:= C_A0*(1-X(W))*(1+X(W))

which has been used as part of the ODE.

I would really like to plot C_A as a function of W. I have no problem plotting X as a function to W using odeplot. Ideally I would like to plot C_A and X vs W in the same plot.

Regards