I'm doing some easy calculations in Maple 2015, but Maples units are acting weird:

I would say that h and h/1 should be the same, but 1/h should give me 1/400 m^2*K*W^-1

If I try to input 1/U__0 it gives me 1/400 m^2*K*W^-1, just like expected

Am I doing anything wrong? Can it be because of my settings?

I'm running Maple 2015 on a Macbook pro running OSX 10.11

I want to plot E with respect to t.

I typed the sys of this equation and try to plot it with DEplot but failed.

This is the code

DEplot([sys], [x(t), y(t), E(t)], t = -25 .. 25, [[x(0) = -.3, y(0) = .2]], scene = [E(t), t], stepsize = 0.5e-1, linecolor = red, arrows = none);

The error is Error, (in DEtools/DEplot/CheckDE) derivatives must be given explicitly.

Eager to know the answer, please help me . Thanks very much.

I am puzzled at the lack of output in using the solve command.  Bellow is some sample code; the main part being the for k loop with values 1 to 5.  k=1 gives complex solutiions, and k=2 to 5 gives real values.  If the for loop is restricted to from 2 to 5 and the printf statement uncommented, everthing works fine.

I have tried other methods like sols:=fsolve(a*x^2+k*x+c, x, complex);  to little avail. I realize the equation is an easy quadratic & is easy to solve by the usual formula, but I'm interested in how the solve command works.  It seems to perform caculations, without any error messages - which I find frustrating!

The code after the for k from... ...do loop just illustrates examples where solve works - some with complex coefficients - which to my mind makes my problem more enigmatic!  I'm using Maple 7 and am just wondering if the solve command has been made easier to use?

   Any help or comments would be most appreciated.

Kind regards,

  David

#Program to investigate the solve function.  Putting k=1 gives complex solutions which halts the program.
> restart:
> interface(imaginaryunit, errorbreak=0, errorcursor=true, labelling=false):
> with(SolveTools):
> a:=1:c:=1:
>

################################
> for k from 1 to 5 do
>   sols:=solve(a*x^2+k*x+c, x):  # assuming x::complex;
>   #printf("k=%d  sols[1]=%5.2f  sols[2]=%5.2f\n", k,eval(sols[1]), eval(sols[2]));
> end do:  #for k

#################################

> printf("End of for loop\n\n");
> sols2:=solve(x^2+I);
> sols2[1];
> sols2[2];
> #sols3:=solve(a*x^3+x^2-I+2);
> solve(z^(I+1)+I,z);
> evalc(op(1,%));  #c=Cartesian
> k:=1:
> sols4:=solve(a*x^2+k*x+c, x):
> #evalc(op(1,%));  #c=Cartesian
> print("Evaluating sols4");
> eval(sols4);
> sols4[1];
> sols4[2];

So I am using the with(Student[MultivariateCalculus]); package to find the maximum and minimum of the fumction xyz to the given constraint: LagrangeMultipliers(x*y*z, [x^2+4*y^2+4*z^2-4], [x, y, z]) and I got 14 points. But to find the global maximum/minimum I need to evaluate all these points in the main function xyz. I tried converting it to a list and doing something and checked out this thread but it's only for single variable stuff so I am not sure how to extrappolate it to my case.

http://www.mapleprimes.com/questions/202529-Evaluating-A-Function-At-More-Than-One-Point#

These were my points by the way, Yeah lots.

[0, 0, 1], [0, 0, -1], [0, 1, 0], [0, -1, 0], [2, 0, 0], [-2, 0, 0], [(2/3)*sqrt(3), (1/3)*sqrt(3), (1/3)*sqrt(3)], [-(2/3)*sqrt(3), -(1/3)*sqrt(3), -(1/3)*sqrt(3)], [(2/3)*sqrt(3), (1/3)*sqrt(3), -(1/3)*sqrt(3)], [-(2/3)*sqrt(3), -(1/3)*sqrt(3), (1/3)*sqrt(3)], [(2/3)*sqrt(3), -(1/3)*sqrt(3), (1/3)*sqrt(3)], [-(2/3)*sqrt(3), (1/3)*sqrt(3), -(1/3)*sqrt(3)], [(2/3)*sqrt(3), -(1/3)*sqrt(3), -(1/3)*sqrt(3)], [-(2/3)*sqrt(3), (1/3)*sqrt(3), (1/3)*sqrt(3)]

Hi everyone,

I wanted to know if it was possible to store symbolic variables in a vector because I have a function of 10 variables which I want to write with Σ, Π and A(l), A being my vector of symbolic variables...

Thank you for your time


Benjamin

Hi. I have this strange error.

Whenever I type D(f)(x) into the maple prompt, the program adds a whitespace between D(f) and (x), so I get the wrong output. I have to go back and delete the space manually. Here is a picture. http://prntscr.com/8vji4k

I type 'D(f)(x)'  and the software displays 'D(f) (x) ' in the prompt, with the extra space.

I am using maple 2015 if that helps, but I think I had the same error with Maple 18

I did not add a space. I literally just entered f:=x->x^2 -3*x + 2; D(f)(x)

but the computer adds a space as I type D(f)(x).

Also I'm not sure why the space ruins the expression

What i am supposed to get is  ' 2x - 3 '

I used to convert the expression to latex code and copy the code to MathType, the insert the expression.

Is there any easier way?

I want the expression I inserted is modifiable, so copy from Maple and paste to Word is not what I want.

Are there any examples of network solutions such as mine systems in Maple.
I wrote in the Maple system of partial differential equations describing the process of filtration combustion.
I'm a novice. I do not quite understand how to solve it.
Online a lot of "simple" examples. I need something very similar to my case.

Model03.mw

How I can write a procedure in Maple that return a equation of line that passes of two points (a,f(a)) and (b,f(b)) on the curve y=f(x) and the final plot y=f(x) and secant line in the same screen?

How I can highlight p(1,1) and Q(2,4) on the curve f(x)=x^2?

Hello,

I´ve got 2-dimensional array (100x100) of values, which I'd like to plot as 3d graph, where x,y axis would be coords in the array and z-axis would be the value there.

Values are formed by procedure, not by function, so I can't use standard 3d plot, that plots a 3d surface. I think the best is to use the pointplot3d function, but you have to assign each point separately. 

I tried to create a list of pointplot3d plots, one for each row of the array, and then display these plots all in one, but I just received GLException error.

Do you have any ideas?

hi all

how can i solve these contemporaneous:

eq1:=(1-Pi*x/2)*(f/2/E)*yc-1/3=Int(t^4/sqrt((t^2-(f/2/E)*yc)^2+ya^2),t=0..1);
eq2:=x^2*yc*(1-Pi*x/2)-1/3=Int(t^4/sqrt((t^2-x^2*yc)^2+ya^2),t=0..1);

for like x=-3.  and f,E are concern.

thank you

Social Golfer Problem

So we have 8 golfers : 2 golfers per group and 4 groups.Over several golfing days, how can they be arranged so no golfer plays with the same player twice.

turns out they can play for 7 days.

So my attempt in maple....golfing.mw

For 3 players per group and 4 groups this is the arrangement over 4 days:

(these was done in wolfram demonstrations project but the code appears to be obfuscated)

have eroror when run command below

animate(dualaxisplot(plot(sin(x+A), x=0..5), plot(cos(x+A), x=0..5), style = line, gridlines = false), A = 0 .. 5);

Dear collagues

Hi,

I write a code to solve a system of ODE. It solve the ODES in a wide range of parameters but as I decrease NBT below 0.5, it doesnt converge. I do my best but I couldn't find the answer. Would you please help me? Thank you

Here is my code and it should be run for 0.1<NBT<10. the value of NBT is input directly in res1.

restart:
EPSILONE:=1000:
Digits:=15:

a[mu1]:=5.45:
b[mu1]:=108.2:
a[k1]:=1.292:
b[k1]:=-11.99:




rhop:=4175:
rhobf:=998.2:
mu1[bf]:=9.93/10000:
k1[bf]:=0.597:

rhost(eta):=1-phi(eta)+phi(eta)*rhop/rhobf;
k:=unapply(k1[bf]*(1+a[k1]*phi(eta)+b[k1]*phi(eta)^2),eta);


eq1:=(diff(u(eta), eta))*a[mu1]*(diff(phi(eta), eta))+2*(diff(u(eta), eta))*b[mu1]*phi(eta)*(diff(phi(eta), eta))+((diff(u(eta), eta))+(diff(u(eta), eta))*a[mu1]*phi(eta)+(diff(u(eta), eta))*b[mu1]*phi(eta)^2)/(eta+EPSILONE)+diff(u(eta), eta, eta)+(diff(u(eta), eta, eta))*a[mu1]*phi(eta)+(diff(u(eta), eta, eta))*b[mu1]*phi(eta)^2+1-phi(eta)+phi(eta)*rhop/rhobf:
eq2:=(1+a[k1]*phi(eta)+b[k1]*phi(eta)^2)*(diff(T(eta), eta))/(eta+EPSILONE) + (a[k1]*(diff(phi(eta), eta))+2*b[k1]*phi(eta)*(diff(phi(eta), eta)))*(diff(T(eta), eta))+(1+a[k1]*phi(eta)+b[k1]*phi(eta)^2)*(diff(T(eta), eta, eta));
eq3:=diff(phi(eta),eta)+phi(eta)/(N_bt*(1+gama1*T(eta))^2)*diff(T(eta),eta):

eq2:=subs(phi(0)=phi0,eq2):
eq3:=subs(phi(0)=phi0,eq3):


eval(dsolve({eq3,phi(1)=phiv},phi(eta)),(T)(1)=1):
Phi:=normal(combine(%)):
Teq:=isolate(eval(eq2,Phi),diff(T(eta),eta)):
ueq1:=eval(eq1,Phi)=0:
ueq2:=subs(Teq,ueq1):


lambda:=0;
Ha:=0;
N_bt:=cc*NBT+(1-cc)*0.8;
kratio:=k1[p]/k1[bf]:






GUESS:=[T(eta) =0.0001*eta, u(eta) =0.1*eta, phi(eta) = 0.3*(eta-1)^4];
res1 := dsolve(subs(NBT=0.48,gama1=0.2,phiv=0.06,{eq1,eq2,eq3,u(0)=lambda*D(u)(0),D(u)(1)=0,T(0)=0,phi(1)=phiv,T(1)=1}), numeric,method=bvp[midrich],maxmesh=4000,approxsoln=GUESS, output=listprocedure,continuation=cc):
G0,G1,G2:=op(subs(subs(res1),[phi(eta),u(eta),diff(T(eta),eta)])):

masst:=evalf(int((1-G0(eta)+G0(eta)*rhop/rhobf)*G1(eta), eta = 0..1));
heatt:=(1+a[k1]*G0(0)+b[k1]*G0(0)^2)*G2(0);

plots:-odeplot(res1,[[eta,T(eta)]],0..1,legend=[T],color=["Black"],linestyle=Solid,axes=boxed,thickness=3);
plots:-odeplot(res1,[[eta,u(eta)]],0..1,legend=[u],color=["Black"],linestyle=Solid,axes=boxed,thickness=3);
plots:-odeplot(res1,[[eta,phi(eta)]],0..1,legend=[phi],color=["Black"],linestyle=Solid,axes=boxed,thickness=3);

>
>

Thank you

Amir