Maple 18 Questions and Posts

These are Posts and Questions associated with the product, Maple 18

In this app you can visualize the location of the points in the different quadrants, also calculate the distance between two points. Finally the calculation of the coordinates of the midpoint. With these applications can be combined to study different cases between distance between two points and midpoint. Generated in Maple for students of secondary education and pre-calculation. In Spanish

Distance_between_two_points_and_midpoint.mw

Lenin Araujo Castillo

Ambassador of Maple

 

Is it possible to increase the execution speed of the dsolve command? For example, is it possible to increase speed with the use of Multithreaded tools?

Thank you for your help

with(plots); R1 := .1; R0 := .1; m := .1; a := .1; Ha := .1; Nt := .1; Nb := .1; Pr := 6.2; Le := .6; Bi := 1; Ec := .1; k := 1; r := .1; A := 1; fcns := {C(y), T(y), U(y), W(y)}; sys := diff(U(y), `$`(y, 2))+(R1*(diff(U(y), y))-2*R0*W(y))*exp(a*T(y))-a*(diff(U(y), y))*(diff(T(y), y))-Ha*(U(y)+m*W(y))*exp(a*T(y))/(m^2+1)-U(y)/k+A*exp(a*T(y)) = 0, diff(W(y), `$`(y, 2))+(R1*(diff(W(y), y))+2*R0*U(y))*exp(a*T(y))-a*(diff(W(y), y))*(diff(T(y), y))-Ha*(W(y)-m*U(y))*exp(a*T(y))/(m^2+1)-W(y)/k = 0, diff(T(y), `$`(y, 2))+R1*Pr*(diff(T(y), y))+Pr*Ec*exp(-a*T(y))*((diff(U(y), y))*(diff(U(y), y))+(diff(W(y), y))*(diff(W(y), y)))+Nt*(diff(T(y), y))*(diff(T(y), y))+Pr*Ec*(U(y)*U(y)+W(y)*W(y))*exp(-a*T(y))/k = 0, diff(C(y), `$`(y, 2))+Pr*Le*R1*(diff(C(y), y))+Nt*(diff(C(y), `$`(y, 2)))/Nb-r*C(y) = 0; bc := U(0) = 0, W(0) = 0, C(0) = 0, (D(T))(0) = Bi*(T(0)-1), U(1) = 0, W(1) = 0, C(1) = 1, T(1) = 0; L := [.5, 1.0, 1.5, 2.0]; AP := NULL; for k to 4 do R := dsolve(eval({bc, sys}, Ha = L[k]), fcns, type = numeric, method = bvp[midrich], AP); AP := approxsoln = R; p1u[k] := odeplot(R, [y, U(y)], 0 .. 1, numpoints = 100, labels = ["y", "U"], linestyle = dash, color = black) end do; display({p1u[1], p1u[2], p1u[3], p1u[4]})

I tried to integrate

int((1-x^floor(u))/((1-x)*u^2), u = 1 .. infinity, numeric)

where x=-1. The result should be log 2 = 0.6931471806. However it gives me 0.6687714032.

When using a numeric cut off, the result improves, so what is the issue here?

6687714032

Hello.

I have this problem when executing the entire worksheet or selected groups.
Also Maple can crash by itself, to its heart's content)
What I can do to solve this problem?
OS: W7 x64, Java is up to date

Thx.

In Physics package there is this compact notation X=(t,x,y,z)

Is there something similar in the VectorCalculus packge?

For example

restart;

with(VectorCalculus);

SetCoordinates(cartesian[x, y, z]);

v := VectorField([vx, vy, vz]);

Jacobian(v);

 

I don't explicitly want to write the arguments (x,y,z) of the functions vx,vy,vz everytime.

untit.mw

 



 

These files contain the kinematics and dynamics of the solid using a new technique (ALT + ENTER) to visualize the results online and thus save space in our Maple worksheet. Seen from a relative approach. For engineering students. In Spanish.

Equations_of_movement_for_particle.mw  (Intro)

Kinematics_and_relative_dynamics_of_a_solid.mw

Flat_kinetic_of_a_rigid_body.mw

Lenin Araujo Castillo

Ambassador of Maple

The video shows the curvilinear components of acceleration in polar coordinates, radial and tangential scalar components. Applied to a structure; in a time interval; to finally be graphed and interpreted. For engineering students.

Speed_and_Acceleration_with_Cylindrical_Components.mw

Lenin Araujo Castillo

Ambassador of Maple

restart;
N:=4;alpha:=5*3.14/180;r:=10;Ha:=5;H:=1;
dsolve(diff(f(x),x,x,x));
Rf:=diff(f[m-1](x),x,x,x)+2*alpha*r*sum*(f[m-1-n](x)*diff(f[n](x),x),n=0..m-1)
+(4-Ha)*(alpha)^2*diff(f[m-1](x),x);
dsolve(diff(f[m](x),x,x,x)-CHI[m]*(diff(f[m-1](x),x,x,x))=h*H*Rf,f[m](x));
f[0](x):=1-x^2;
for m from 1 by 1 to N do
CHI[m]:='if'(m>1,1,0);
f[m](x):=int(int(int(CHI[m]*(diff(f[m-1](x),x,x,x))+h*H(diff(f[m-1](x),x,x,x))
+2*h*H*alpha*r*(sum(f[m-1-n](x)*(diff(f[n](x),x)),n=0..m-1))+4*h*H*alpha^2*
(diff(f[m-1](x),x))-h*H*alpha^2*(diff(f[m-1](x),x))*Ha,x),x)+_C1*x,x)+_C2*x+_C3;
s1:=evalf(subs(x=0,f[m](x)))=0;
s2:=evalf(subs(x=0,diff(f[m](x),x)))=0;
s1:=evalf(subs(x=1,f[m](x)))=0;
s:={s1,s2,s3}:
f[m](x):=simplify(subs(solve(s,{_C1,_C2,_C3}),f[m](x)));
end do;
f(x):=sum(f[1](x),1=0..N);
hh:=evalf(subs(x=1,diff(f(x),x))):
plot(hh,h=-1.5..-0.2);
A(x):=subs(h=-0.9,f(x));
plot(A(x),x=0..1);

hello! i have a problem about DEplot. can some of you help me to solve this problem? I use Maple 18. here the problem I've

restart;
with(DEtools);
 
>DE3:={diff(y(x),x)=y(x)-z(x),diff(z(x),x)=z(x)-2*y(x)};    
>DEplot(DE3,[y(x),z(x)],x=0..3,y=0..2,z=-4..4,arrows=large);

   when i enter it, I dont get the graphic. can you tell me why? thank you!


 

``

lambda[1] := .3:

evalf(int(2*alpha^2*Z*exp(lambda[1]*Z)/((exp(lambda[1]*Z)-1+alpha)^2*(exp(lambda[2]*Z)-1+alpha)), Z = 0 .. infinity))

Float(undefined)

(1)

``


 

Download aquestion.mw

Dear Maple primes,

Could you, please, help me with numerical solution of an ODE?

The ODE looks like this

dz/dx = f1(x,z) + f2(z)

where f1(x,z) is some simple function of x and z (that does not create any problem), but f2(z) is given as

f2(z) = int(f3(t), t = z1..z2)

The problem appears, when the integral cannot be solved analytically.

Below is an example of the problem (here I chose the function f3(t)= tt as well as other functions, intervals and initial condition only for the sake of illustration of the problem):

restart; with(plots)

INT := Int(t^t, t = .1 .. z(x), method = _DEFAULT)

eq1 := {diff(z(x), x) = x+z(x)+INT, z(.1) = .1}

plot1 := dsolve(eq1, type = numeric, range = .1 .. 1)

odeplot(plot1)


Download z-for_primes_dsolve.mw

Thank you in advance!

Max

restart; with(plots);
[animate, animate3d, animatecurve, arrow, changecoords, 

  complexplot, complexplot3d, conformal, conformal3d, 

  contourplot, contourplot3d, coordplot, coordplot3d, 

  densityplot, display, dualaxisplot, fieldplot, fieldplot3d, 

  gradplot, gradplot3d, implicitplot, implicitplot3d, inequal, 

  interactive, interactiveparams, intersectplot, listcontplot, 

  listcontplot3d, listdensityplot, listplot, listplot3d, 

  loglogplot, logplot, matrixplot, multiple, odeplot, pareto, 

  plotcompare, pointplot, pointplot3d, polarplot, polygonplot, 

  polygonplot3d, polyhedra_supported, polyhedraplot, rootlocus, 

  semilogplot, setcolors, setoptions, setoptions3d, spacecurve, 

  sparsematrixplot, surfdata, textplot, textplot3d, tubeplot]


fixedparameter1 := [n = .3, W[e] = .3, M = .2, gamma = 1, delta = -1, N[r] = .8, Pr = .72, Nb = .5, Nt = .5, Bi = 2, Pr = .72, Le = 5];
[n = 0.3, W[e] = 0.3, M = 0.2, gamma = 1, delta = -1, N[r] = 0.8, 

  Pr = 0.72, Nb = 0.5, Nt = 0.5, Bi = 2, Pr = 0.72, Le = 5]


eq1 := (1-n)*(diff(f(eta), eta, eta, eta))+f(eta)*(diff(f(eta), eta, eta))-M*(diff(f(eta), eta))+n*W[e]*(diff(f(eta), eta, eta, eta))*(diff(f(eta), eta, eta)) = 0;
        /  d   /  d   /  d         \\\
(1 - n) |----- |----- |----- f(eta)|||
        \ deta \ deta \ deta       ///

            /  d   /  d         \\     /  d         \
   + f(eta) |----- |----- f(eta)|| - M |----- f(eta)|
            \ deta \ deta       //     \ deta       /

            /  d   /  d   /  d         \\\ /  d   /  d         \\   
   + n W[e] |----- |----- |----- f(eta)||| |----- |----- f(eta)|| = 
            \ deta \ deta \ deta       /// \ deta \ deta       //   

  0
deq1; eval(eq1, fixedparameter1);
    /  d   /  d   /  d         \\\
0.7 |----- |----- |----- f(eta)|||
    \ deta \ deta \ deta       ///

            /  d   /  d         \\       /  d         \
   + f(eta) |----- |----- f(eta)|| - 0.2 |----- f(eta)|
            \ deta \ deta       //       \ deta       /

          /  d   /  d   /  d         \\\ /  d   /  d         \\   
   + 0.09 |----- |----- |----- f(eta)||| |----- |----- f(eta)|| = 
          \ deta \ deta \ deta       /// \ deta \ deta       //   

  0
eq2 := (1+(4/3)*N[r])*(diff(theta(eta), eta, eta))+Pr*f(eta)*(diff(theta(eta), eta))+Nb*(diff(phi(eta), eta))*(diff(theta(eta), eta))+Nt*(diff(theta(eta), eta))*(diff(theta(eta), eta)) = 0;
          /    4     \ /  d   /  d             \\
          |1 + - N[r]| |----- |----- theta(eta)||
          \    3     / \ deta \ deta           //

                         /  d             \
             + Pr f(eta) |----- theta(eta)|
                         \ deta           /

                  /  d           \ /  d             \
             + Nb |----- phi(eta)| |----- theta(eta)|
                  \ deta         / \ deta           /

                                    2    
                  /  d             \     
             + Nt |----- theta(eta)|  = 0
                  \ deta           /     
deq2; eval(eq2, fixedparameter1);
                      /  d   /  d             \\
          2.066666667 |----- |----- theta(eta)||
                      \ deta \ deta           //

                           /  d             \
             + 0.72 f(eta) |----- theta(eta)|
                           \ deta           /

                   /  d           \ /  d             \
             + 0.5 |----- phi(eta)| |----- theta(eta)|
                   \ deta         / \ deta           /

                                     2    
                   /  d             \     
             + 0.5 |----- theta(eta)|  = 0
                   \ deta           /     
eq3 := diff(phi(eta), eta, eta)+Pr*Le*f(eta)*(diff(phi(eta), eta))+Nt*(diff(theta(eta), eta, eta))/Nb = 0;
    /  d   /  d           \\                /  d           \
    |----- |----- phi(eta)|| + Pr Le f(eta) |----- phi(eta)|
    \ deta \ deta         //                \ deta         /

            /  d   /  d             \\    
         Nt |----- |----- theta(eta)||    
            \ deta \ deta           //    
       + ----------------------------- = 0
                      Nb                  
deq3 := eval(eq3, fixedparameter1);
    /  d   /  d           \\               /  d           \
    |----- |----- phi(eta)|| + 3.60 f(eta) |----- phi(eta)|
    \ deta \ deta         //               \ deta         /

                     /  d   /  d             \\    
       + 1.000000000 |----- |----- theta(eta)|| = 0
                     \ deta \ deta           //    
bcs1 := f(0) = 0, D(f)(0) = 1+gamma*(D@D)(F)(0)+delta*(D@D@D)(f)(0), D(f)(8) = 0;
 f(0) = 0, 

   D(f)(0) = 1 + gamma @@(D, 2)(F)(0) + delta @@(D, 3)(f)(0), 

   D(f)(8) = 0
bc1 := eval(bcs1, fixedparameter1);
   f(0) = 0, D(f)(0) = 1 + @@(D, 2)(F)(0) - @@(D, 3)(f)(0), 

     D(f)(8) = 0
bcs2 := D(theta)(0) = Bi*(theta(0)-1), theta(8) = 0;
         D(theta)(0) = Bi (theta(0) - 1), theta(8) = 0
bc2 := eval(bcs2, fixedparameter1);
           D(theta)(0) = 2 theta(0) - 2, theta(8) = 0
bcs3 := Nb*D(phi)(0)+Nt*D(theta)(0) = 0, Nb*D(phi)(0)+Nt*D(theta)(0) = 0, phi(8) = 0;
        Nb D(phi)(0) + Nt D(theta)(0) = 0, 

          Nb D(phi)(0) + Nt D(theta)(0) = 0, phi(8) = 0
bc3 := eval(bcs3, fixedparameter1);
       0.5 D(phi)(0) + 0.5 D(theta)(0) = 0, 

         0.5 D(phi)(0) + 0.5 D(theta)(0) = 0, phi(8) = 0
R := dsolve({bc1, bc2, bc3, deq1, deq2, deq3}, [f(eta), theta(eta), phi(eta)], numeric, output = listprocedure);
Error, (in dsolve/numeric/process_input) system must be entered as a set/list of expressions/equations


 

Dear Maple Primes,

could you, please, help me with numeric integration? I’m new in numeric integration and can’t reach desired precision of a result.
Here is the integral f(xmax) that I try to compute for different values of xmax from the interval 0.025..0.24 :

f:=(xmax)->Int(K*F*Int(G*F,x=x..xmax,method=integrationmethod),x=x0..xmax,method=integrationmethod)

where x0 is lower limit of outer integral, x0 := 0.025

and K, F and G are functions of x

K:=x-x0

F:=(a1+a2*x+a3*x2+a4*x5)/(b1*x+b2*x2+b3*x6)

G:=exp(c1+c2*x+c3*x7)

with

a1:=8e3; a2:=6e4; a3:=3e4; a4:=1.8e8;
b1:=9.2e17; b2:=1.1e18; b3:=4.6e21;
c1:=8.202046; c2:=-12.31377; c3:=-818043.42;

Please, notice, that G (as well as G*F) is a steeply decreasing function on the interval x = 0.025..0.24.

I get "a seemingly correct" result (that means that f increases as xmax intreases), when I try to plot f(xmax) for the following "guessed" options

Digits:=15
integrationmethod:=_d01akc
plot(f,0.21..0.24,color=black)

What is puzzling me is that I get a different "seemingly correct" result, when I modify the integral f by,
at fist, multiplying G by a constant (for example Const:=1e20; G:=Const*exp(c1+c2*x+c3*x7) )
and, second, plotting the f divided by this constant:

plot(f/Const,0.21..0.24,color=red)

The following Figure presents the values of f plotted versus xmax with (red curve) and without (black curve) using of the constant Const:

Dear Primes, could you, please, comment on this difference? Because the only indicator that I have (from the analysis of G, F and K) is that f must be a monotonically (and stricktly) increasing function of xmax.

Please, find the maple worksheet in attachment.

Thank you in advance!
Maks

for_primes_numeric_integration_v02.mw

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