When the solution is obtained in symbolic form, and then numeric values are assigned to variables, the answer is different from the numerical solution.

vol := -R^2*Pi*H*(-3*R*C^2*sin(theta)-3*H^2*cos(theta)^2*sin(theta)*R+6*R*C*sin(theta)*cos(theta)*H-sin(theta)*R^3+sin(theta)*R^3*cos(theta)^2+C^3-3*C^2*cos(theta)*H-cos(theta)^3*H^3+3*H^2*C*cos(theta)^2+3*R^2*H*cos(theta)^3+3*R^2*C-3*R^2*H*cos(theta)-3*cos(theta)^2*R^2*C)/(3*(H^2*cos(theta)^2-R^2+cos(theta)^2*R^2)^(3/2)):

V := (1/3)*Pi*R^2*H:

vp := Pi*h*R^2*(3*H^2-3*H*h+h^2)/(3*H^2):

eq := V-vp = vol;

va := theta = (1/6)*Pi, R = 2, H = 20, h = 14;

Symbolic solution:
sc := solve(eq, [C]);
evalf(subs(va, sc));
   [[C = 18.36540754], [C = 18.29805834 + 0.03888407898 I],  [C = 18.29805834 - 0.03888407898 I]]

Numerical solution:
eq1 := subs(va, eq);
evalf(solve(eq1, [C]));
    [[C = 20.91425055 + 4.492493739 I], [C = 20.91425055 - 4.492493739 I], [C = 13.13302314]]

Why this happens?
I am grateful for your attention.
Sinval Oliveira Santos.

hello people

I have this computation which has to do with my undergraduate project and each time I compute some work (vary parameters), it seems to evaluate forever. although my computer isn't recent and has 2GB of RAM the computation didn't seem to me as much of a task for it. computation works fine with some parameters as 0 but the moment I change it to a natural number, it evaluates forever.

Is there anyway I could speed up computation in maple? or do I just need a faster computer? but I have a dead line for next week. can I upload my worksheet for someone here to help me execute? 

thank you in advance. 

I want to extract all the symbols and last trade from 

http://finance.yahoo.com/q/cp?s=%5EIXIC

I have tried:

status, data, headers := HTTP:-Get("http://finance.yahoo.com/q/cp?s=%5EIXIC");
data;

but it just gives me a bunch of jiberish! Any ideas?

I want to solve numerically the nonlinear pde:

u_x+u_t - (u_{xt})^2 = u(x,t)

which method do you propose me to use with maple? (I don't mine about which boundary conditions to be used here).

I have a function fitted and found the coeffiecients, the coeffiecient values are found with data from maple

the function is: a*(x+b/c)

my result is 5x+15

How do I get the values of a, b and c? The value of a is 5 that I know, but how does I get that maple gives me all the values of a,b  and c? The problem is that I get one value while i need the values of a, b and c.

Thanks

I recently got myself a 64 bit computer and have noticed that I cannot use the option compile=true in dsolve/numeric. Take the following simple example:

dsolve({diff(x(t),t)=x(t),x(0)=1},numeric,compile=true);
Error, (in dsolve/numeric/SC/preproc) unable to compile (rc=1), please try again, and if that fails verify your Windows compiler installation

I'm using Windows 10, but had the same problem with Windows 8.1 on the same machine.
The Compiler:-Compile examples in the help page all work.

What do I have to do to make the option compile=true work in dsolve/numeric?

You may safely assume that I don't know any technicalities about these things.

How to change the font style, globally, the inputs and outputs of computations in Maple 2015? That is, every time a new document is started, the chosen style is automatically applied.

Oliveira.

Hello there..I tried to plot this program n somehow it didnt work.. I dont know how to fix it (I'm a beginner user)..Can anyone help me?? Please..

Thanks a lot

--------------------------------------------------

hmin := .2;

tclose := 150;

topen := 120;

B0 := 0; B1 := 800; dB := (B1-B0)*(1/100);

B := dB*i+B0;

xcoor := [seq(B, i = 0 .. 99)];

ycoor := [seq(fsolve(tclose*ln((1-(1-hmin)*exp((-B+APD)/topen))/hmin) = APD), i = 0 .. 99)];

with(plots);

P := plot(xcoor, ycoor);

display(P)

Hello everyone!

Do you have any idea to solve and plot a 2-time logistic map:

x(t+ 1_\alpha)= r*x(t)*(1-x(t))  ,t=(t^1,t^2)  ?

Thank you

There are no examples for ModuleDeconstruct either on its help page or in the Programming Guide. Of course, I can figure out its basic and primarily intended purpose: to render the module/object in a one-dimensional plaintext printed form, which would be useful for debugging. But I am most interested in this use described in the second sentence of this, the second paragraph of Description at ?ModuleDeconstruct [italics added]:

When the value returned by ModuleDeconstruct is printed, the output could be capable of being parsed to the original module. When used with an object, ModuleDeconstruct can return an unevaluated call to a constructor to achieve this.

That seems very powerful. Is there any example of it being used in Maple library code? in user code? Can anyone here come up with a practical use for this? A Google search turns up nothing.

Hi,

  I have the following input in order to obtain the dimension of an array, by means of the values has been assigned

with(ArrayTools):
with(LinearAlgebra):
f[1]:=1:
f[2]:=2:
nops(f);
Size(f);
Dimension(f);

  The result is 

---

1
[ 1 1 ]
Error, invalid input: LinearAlgebra:-Dimension expects its 1st argument, A, to be of type {Matrix, Vector} or coercible via `~Simplify`, but received f

 ---

I cannot get number "2", which is expected. Is there any way to obtain that? I looked for help and mapleprime, without any simple solution ......

Thank you very much!

I want to compute the following solve:

C:=A, B, F, H(It has 4 unknowns):

V:=R,Y,E,I (It has 4 equations):

solve({V},{C});

By hand calculations I just found that the solve result is real ,but in maple there is no solution and no error (the maple ignores to solve this equation !!!) 

can anybody help me to find the solve soltuion ?

Thank you 

H. Kabir

The font size in the output pane of the standard interface, interactive debugger is really, really small and I can't figure out how to increase it. (Other than drop my screen resolution from its native 2560x1440, which makes it bigger but "fuzzier" - not a huge improvement for tired eyes!!)

Hi dear friends

How do I improve my ability to manipulate code?

Thanks

_________________________________________________________________________________________

restart:

Digits := 30: m := 20: p0 := 8.: g := -0.3: nu := 0.3: a := 1:

w := sum(b[n]*r^(1.02*n), n = 1 .. m):

ODE := r^3*(g*r+a)^3*(diff(w, r, r, r, r))+2*(diff(w, r, r, r))*r^2*(4*g*r+a)*(g*r+a)^2+(diff(w, r, r))*r*(3*g^3*nu*r^3+P*a^3*r^2+6*a*g^2*nu*r^2+11*g^3*r^3+3*a^2*g*nu*r+15*a*g^2*r^2+3*a^2*g*r-a^3)+(diff(w, r))*(6*g^3*nu*r^3+P*a^3*r^2+6*a*g^2*nu*r^2-2*g^3*r^3-3*a*g^2*r^2+a^3):

for P from p0 by 0.1e-1 to p0+1 do
W := simplify(subs(solve({seq(evalf(subs(r = j/(m+2), ODE)), j = 2 .. m-1), subs(r = 1, diff(w, r))}, {seq(b[j], j = 1 .. m)}), w/b[m])):
F := (int(((diff(W, `$`(r, 2))+(diff(W, r))/r)^2-(2*(1-nu))*(diff(W, `$`(r, 2)))*(diff(W, r))/r)*r*(1+g*r/a)^3, r = 0 .. a))/(int((diff(W, r))^2*r, r = 0 .. a)):
delta[trunc(100*(P-p0))] := abs(F-P) end do:

plot(W, r = 0 .. a);

Min := min(seq(delta[j], j = 0 .. 100)):

for j from 0 to 100 do if delta[j] = Min then print(p0+j/(100.)) else  end if end do;