restart;

K := -3;
                               -3
m := 1;
                               1
w := -4*K;
                               12
alpha[0] := -2;
                               -2
alpha[1] := 0;
                               0
a := 2;
                               2
b := 3;
                               3
                               1
beta[1] := (12*(m^2+K))/(a+b);
                              -24
                              ---
                               5 
xi := -t*w+x+y;
                         -12 t + x + y

F := -sqrt(-K)*tanh(sqrt(-K)*xi);
                (1/2)     / (1/2)                \
              -3      tanh\3      (-12 t + x + y)/
U := alpha[0]+alpha[1]*(m+F)+beta[1]/(m+F);
                                 24                     
        -2 - -------------------------------------------
               /     (1/2)     / (1/2)                \\
             5 \1 - 3      tanh\3      (-12 t + x + y)//
                               1
y := 0;
                               0

plot3d(U, x = -10 .. -10, t = -10 .. 10);

t := 0;
                               0
plot(U, x = -10 .. 10);

RootOf(_Z^2*beta*h[1]-alpha*l[1]*l[2], label = _L2)

Hi I have the following ln function that I want to differentiate wrt variable c:

I2 := -sqrt(-c^2+1)*ln(abs((.9*sqrt(-c^2+1)-c*sqrt(1-.9^2))/(-.9*sqrt(-c^2+1)-c*sqrt(1-.9^2))))

When I differentiate I obtain an expression that involves 

...abs(1, (.9*sqrt(-c^2+1)-.4358898944*c)/(-.9*sqrt(-c^2+1)-.4358898944*c))...

Why does it give a comma at the abs expression? how to get rid of that.

Hello everyone,

I have a function of 5 variables, A, P, N, k. I want to solve and express as a power series of 'k'

w=F*k+G+H/k+...

and gather the coefficients of each power.

However, the result I obtain in my code differs from the analytical value I found. What am I doing wrong?

Thanks!

collect_mp.mw

How to get a plot for different values of Mh.

like Mh=[1 2 3 4]

Code:

restart;
with(DEtools,odeadvisor);

m:=10;H:=1;Mh:=1;b:=0.02; a:=0.05;V:=array(0..m); V[0]:=1-exp(-t);

for k from 1 to m do

if k=1 then chi:=0;

 chi:=1;

 fi;

 p:=0;

 for j from 0 to k-1 do

   p:=p+(V[k-1-j]*diff(V[j],t$2)-diff(V[k-1-j],t)*diff(V[j],t)-a*(2*diff(V[k-1-j],t)*diff(V[j],t$3)-diff(V[k-1-j],t$2)*diff(V[j],t$2)-V[k-1-j]*diff(V[j],t$4)));  od;

p:=(p+diff(V[k-1],t$3)-b*(diff(V[k-1],t$2)+t*diff(V[k-1],t$3))-Mh*diff(V[k-1],t))*h*H;

p:=factor(p);

V[k]:=(-int(p,t)+0.5*exp(t)*int(exp(-t)*p,t)+0.5*exp(-t)*int(exp(t)*p,t)+chi*V[k-1]+C1+C3*exp(-t));

v:=unapply(V[k],t);

V[k]:=frontend(expand,[V[k]]);  V[k]:=subs(C3=solve(eval(subs(t=0,diff(V[k],t))),C3),V[k]); V[k]:=frontend(expand,[V[k]]);

V[k]:=subs(C1=solve(eval(subs(t=0,-V[k]-diff(V[k],t))),C1),V[k]);

od:

appr:=0;

for k from 0 to m do

 appr:=appr+V[k];

od:

u_appr:=unapply(appr,(h,t)):

u_appr_1:=unapply(diff(u_appr(h,t),t),(h,t)):

evalf(u_appr_1(-0.4,t)):

with(plots);

plot([u_appr_1(-0.4,t)],t=0..4,0..1.2,color=[black],axes=frame):

this plot for Mh=1:

How to apply two for loops to solve ode problem.

code:

restart; with(plots); fcns := {T(eta), f(eta)};
m := .5; bet := 1; na := 1/6; N := 5;
eq1 := (diff(f(eta), `$`(eta, 3)))*pr+m-m*(diff(f(eta), `$`(eta, 1)))+((m+1)*(1/2))*(diff(f(eta), `$`(eta, 2)))*f(eta) = 0;
eq2 := diff(T(eta), `$`(eta, 2))+((m+1)*(1/2))*(diff(T(eta), `$`(eta, 1)))*f(eta) = 0;
bc := f(0) = 0, (D(f))(0) = 0, (D(f))(N) = 1, (D(T))(0) = -bi*(1-T(0)), T(N) = 0;
bi:= [seq(1..4,0.1)];  NN := nops(bi);  
pr:=[seq(1..2,0.1)];  NN1 := nops(pr);
for i  from 1 to NN do    
for j from 1 to NN1 do  
R := dsolve(eval({bc, eq1,eq2}, bi[i],pr[j]), fcns, type = numeric, method = bvp[midrich], maxmesh=2400):  
X1||[i,j]:=rhs(-R(0)[3]):
end do:  
end do:  

Have a good day.
 

I am trying to expand a multivariable (more specifically 4 variables) function in powers of one of its variables when it goes to infinity.

However, the result I get is always zero, even if I input (or not) values for some of the other variables.

Can anybody help?

series_expansion.mw

P.s.: I want to do the same for the other two functions I defined in the worksheet as well.

Download badSums2.mw

Dear friends,

Greetings.

How to get the second solution.

how to change the guess value in maple.

figure 1 plot in Matlab with two different initial guesses.

TWOSOLUTION.mw

Download Dtm.mw

Hi,

Due to an unexpected maintenance operation, I had to uninstall Maple 18 from my Windows 7-64 bit PC.

Later on I installed it without any problems but, to my surprise now I can't configure it properly. This is:

* Enabling Maple Text as Input (classical input method)
* Removing numbers from equations
* Setting Maple language to English (it took Spanish by default because of Windows)
* Hiding left panel

As usual, this is performed under Tools/Options/Interface and so on...

After I modify my preferred settings, apply globally and close-open again, the program is again in its original form.

How can I do in this case? I have installed it several times. It is also worth noting that the maintenance that I performed was related to deep Windows registry modifications. 

Thanks and regards.

I have a PDE system that relates four functions: sht1, svt1, Lt1, Jirt1.

I'm trying to solve this system numerically, but the pdsolve command returns an error (this error does not make sense to me).

Where am I going wrong?

Thanks!

Test.mw

restart;
T := -S(xi)*S(xi)+mu*R(xi)-lambda;
                        2                    
                  -S(xi)  + mu R(xi) - lambda
Q := -S(xi)*R(xi);
                          -S(xi) R(xi)
u := a[0]+a[1]*S(xi)+b[1]*R(xi);
                 a[0] + a[1] S(xi) + b[1] R(xi)
diff(u, xi);
                  / d        \        / d        \
             a[1] |---- S(xi)| + b[1] |---- R(xi)|
                  \ dxi      /        \ dxi      /
Fr := Q*b[1]+T*a[1];
                         /      2                    \     
     -S(xi) R(xi) b[1] + \-S(xi)  + mu R(xi) - lambda/ a[1]
diff(Fr, xi);
       / d        \                    / d        \     
      -|---- S(xi)| R(xi) b[1] - S(xi) |---- R(xi)| b[1]
       \ dxi      /                    \ dxi      /     

           /         / d        \      / d        \\     
         + |-2 S(xi) |---- S(xi)| + mu |---- R(xi)|| a[1]
           \         \ dxi      /      \ dxi      //     
d := -T*R(xi)*b[1]-S(xi)*Q*b[1]+(-2*S(xi)*T+mu*Q)*a[1];
 /      2                    \                   2           
-\-S(xi)  + mu R(xi) - lambda/ R(xi) b[1] + S(xi)  R(xi) b[1]

     /         /      2                    \                 \   
   + \-2 S(xi) \-S(xi)  + mu R(xi) - lambda/ - mu S(xi) R(xi)/ a[

  1]
diff(d, xi);
 /         / d        \      / d        \\           
-|-2 S(xi) |---- S(xi)| + mu |---- R(xi)|| R(xi) b[1]
 \         \ dxi      /      \ dxi      //           

     /      2                    \ / d        \     
   - \-S(xi)  + mu R(xi) - lambda/ |---- R(xi)| b[1]
                                   \ dxi      /     

                        / d        \        2 / d        \        /
   + 2 S(xi) R(xi) b[1] |---- S(xi)| + S(xi)  |---- R(xi)| b[1] + |
                        \ dxi      /          \ dxi      /        \
   / d        \ /      2                    \
-2 |---- S(xi)| \-S(xi)  + mu R(xi) - lambda/
   \ dxi      /                              

             /         / d        \      / d        \\
   - 2 S(xi) |-2 S(xi) |---- S(xi)| + mu |---- R(xi)||
             \         \ dxi      /      \ dxi      //

        / d        \                  / d        \\     
   - mu |---- S(xi)| R(xi) - mu S(xi) |---- R(xi)|| a[1]
        \ dxi      /                  \ dxi      //     
h := -(-2*S(xi)*T+mu*Q)*R(xi)*b[1]-(-S(xi)^2+mu*R(xi)-lambda)*Q*b[1]+2*S(xi)*R(xi)*b[1]*T+S(xi)^2*Q*b[1]+(-2*T*(-S(xi)^2+mu*R(xi)-lambda)-2*S(xi)*(-2*S(xi)*T+mu*Q)-mu*T*R(xi)-mu*S(xi)*Q)*a[1];
 /         /      2                    \                 \       
-\-2 S(xi) \-S(xi)  + mu R(xi) - lambda/ - mu S(xi) R(xi)/ R(xi) 

           /      2                    \                 
  b[1] + 3 \-S(xi)  + mu R(xi) - lambda/ S(xi) R(xi) b[1]

                         /                                2         
          3              |   /      2                    \          
   - S(xi)  R(xi) b[1] + \-2 \-S(xi)  + mu R(xi) - lambda/  - 2 S(xi

    /         /      2                    \                 \
  ) \-2 S(xi) \-S(xi)  + mu R(xi) - lambda/ - mu S(xi) R(xi)/

                                                             \   
        /      2                    \                 2      |   
   - mu \-S(xi)  + mu R(xi) - lambda/ R(xi) + mu S(xi)  R(xi)/ a[

  1]
collect(expand(h+3*Fr*Fr+(4*omega+3)*Fr), S(xi), R(xi));
     /      2         \      4
R(xi)\3 a[1]  - 6 a[1]/ S(xi) 

                                                  3        /  
   + R(xi)(6 R(xi) a[1] b[1] - 6 b[1] R(xi)) S(xi)  + R(xi)\3 

       2     2                  2                   
  R(xi)  b[1]  - 6 R(xi) mu a[1]  + 12 a[1] mu R(xi)

                  2                                        \ 
   + 6 lambda a[1]  - 8 a[1] lambda - 4 omega a[1] - 3 a[1]/ 

       2        /        2                       2        
  S(xi)  + R(xi)\-6 R(xi)  mu a[1] b[1] + 6 R(xi)  mu b[1]

   + 6 R(xi) lambda a[1] b[1] - 5 R(xi) lambda b[1]

                                      \              /      2   2 
   - 4 R(xi) omega b[1] - 3 b[1] R(xi)/ S(xi) + R(xi)\3 a[1]  mu  

       2            2      2         2                
  R(xi)  - 3 a[1] mu  R(xi)  - 6 a[1]  mu R(xi) lambda

   + 5 a[1] mu R(xi) lambda + 4 omega a[1] mu R(xi)

           2       2                                  2
   + 3 a[1]  lambda  + 3 a[1] mu R(xi) - 2 a[1] lambda 

                                        \
   - 4 omega a[1] lambda - 3 a[1] lambda/

Download vectormatrix.mw

Hello;

 I am trying to verify the analytic solution of a electric and magnetic fields created by a small dipole antenna (also called "Hertzian dipole"). The study of a small dipole is ground zero of anyone learning about antennas as calculations are "relatively" easy if a mathematical software is used. As the title suggests, the fieldplot3d returns an empty box.

Here is some introduction for the problem in question:

 The procedure is relatively straightforward, first, current density vector is defined, from there, magnetic vector potential (named "vector A") is calculated. The curl of vector A gives the magnetic field (named "B-field") produced by the antenna. From B-field, H field is deduced as it is only a multiplication of the B-field by a constant.

 At this point, I try to plot the H-field, and it works like a charm. No problem at all.

The electric field (named "E-field") then, may be calculated by taking the curl of the H-field and multiplying by a constant.

 At this second point, I try to plot the E-field, however, Maple returns an empty box. 

First, I thaught, maybe it was a problem of division by 0, however, after redefining the axis ranges, the problem still persists. I am attaching the code and the images. Any help will be greatly appreciated.

PS: This is my first post and I am very new to maple, please indulgde me if I make some formatting and/or post mistakes

KB

Download short_dipole_matrix_way_old_school.mw