I want to plot the following equation

((1/2)*x*tan(log((1/5)*(2*(x^2+y^2)))) = y

I tried:

with(plots, implicitplot)

implicitplot((1/2)*x*tan(log((1/5)*(2*(x^2+y^2)))) = y, x = -5 .. 5, y =-5..5, numpoints = 1000, gridrefine = 6, color = red)

but result is strange... 

How to change the numer of hatchings in a 3d plot?

Hello, I have a function defined as

                                                   g :=  (x, y)->diff(u1(x, y), x, x)+diff(u2(x, y), x, y). 

I want to define another function as follows

                                                           f :=  (y) ->subs(x = 0, g(x, y)) ,

Now, when I want to calculate numerical values for the new function f(0), f(0.1), f(0.2),..... and so on. The following massage appear

Error, (in f) invalid input: diff received 0, which is not valid for its 2nd argument.

What is the problem here.

Amr
 

I'm curious to know if anyone has written a procedure to optimize the VRP with time windows / constraints.

I have a system of ode's

restart:with(plots):
eq1:=((diff(f(x),x$3)))+f(x)*diff(f(x),x$2)-a*diff(f(x),x$1)^2=0;
eq2:=(diff(g(x),x$2))+b*f(x)*diff(g(x),x$1)=0;
bc1:=f(0)=0,D(f)(0)=1,D(f)(5)=0,g(0)=0.5,g(5)=0;

dsolve can solve it easily.

sol:=dsolve(subs(a=0.5,b=0.5,{bc1,eq1,eq2}), numeric):

Now I was to use the numerical data from the sol in the following expression

Expr:=a*f(x)+b*g'(x)+c*f'(x)*g(x) # at x=1:

to make a table of this form a  b  c  Expr, where a, b, c vary simultaneously between 0 and 1 by 0.2 producing data for Expr.

Any suggestions? 

Hi everyone!

I have a question: what is the simpliest way to generate colorbar for spectrogram?

Now I use "valuesplit" to assign dependece "z"-value from color.

My programm. My test file: "Signal.txt".

filtered_spectrogram.mw

Signal.txt

P.S. I use Maple 2016.

Helle everybohy,

I need to setup a metric tensor in 3-d but with the varalble r, and .  So I try this:

>with(Physics); Setup(mathematicalnotation = true, dimension = 3)

>Setup(coordinates = spherical[r, theta, varphi], metric = M)

where M is the metric that I need to use.  But the last command does not work.  Il I don't write [r, theta, varphi], it work but it's r, theta and t.

Any hint on this please?

Thank you in advance for your help.

Mario Lemelin

mario.lemelin@cgocable.ca

all
I need your help  to give an answer to  this question
I would like to construct a matrix with condtion that comes in picture
How can i do this with maple????
my matrix is n+1*n+1

Hi all,

How to calculate this integral:

for k>0,m>0

Int(exp(-(1/2)*v/k)*v^3*exp((1/2)*v/m)*Ei(1, -(1000*I)*v+(1/2)*v/m), v = 0 .. infinity)

I'm  tried to take advantage of with(IntegrationTools) but I failed

and and I got a strange result ,like this:

Integral.mw

Can somebody execute this code on a powerful comp and report the result in MaplePrimes? That would be kind of her/him.

Download want_for_execution.mw

How do I convince MAPLE to simplify this Euclidean norm? > (D[1](P))(rho, theta, phi); Vector[column](%id = 230612588) > Norm(%, 2); / 2 2 2\ \|cos(phi) sin(theta)| + |sin(phi) sin(theta)| + |cos(theta)| /^ (1/2) > simplify(%, trig); / 2 2 2\ \|cos(phi) sin(theta)| + |sin(phi) sin(theta)| + |cos(theta)| /^ (1/2)

In the TransformTetrad command we can use some parameters, including nullrotationwithfixedl_. However, the nullrotationwithfixedl_ parameter requires another parameter E. How do I enter parameter E?

Thanks,

Denis.

> restart; with(VectorCalculus);
> P := proc (rho, theta, phi) options operator, arrow; `<,>`(rho*cos(phi)*sin(theta), rho*sin(phi)*sin(theta), rho*cos(theta)) end proc;
> r[1] := proc (t) options operator, arrow; P(2, (1/2)*Pi, t) end proc;
> F := VectorField(`<,>`(x, VectorCalculus[`+`](y, R), z), coords = cartesian[x, y, z]);
> F[1] := evalVF(F, r[1](t));
                Vector[column](%id = 255051836)
> F[1] := evalVF(F, r[1](t));
Error, invalid input: VectorCalculus:-evalVF expects its 1st argument, F, to be of type {procedure, Vector(algebraic)}, but received Vector(3, {(1) = Vector(3, {(1) = 2*cos(t), (2) = 2*sin(t)+R, (3) = 0}, attributes = [space = (module () local _origin, _coords, _coords_dim; export GetCoordinates, GetRootPoint, Vector; end module)]), (2) = y+R, (3) = z}, attributes = [vectorfield, coords = cartesian[x, y, z]])
> 

Hey,

    I'm doing a little experimenting on Maple and I want to display 3 Matrixes side by side with text explaining what is what. I have a for cycle in which 5 sets of 3 matrixes are made. And my goal is to display each of the 5 sets.
How would I go about doing that? I've tried the following:

display(Array(print(cat("Matriz A", k, AA[k])), print(cat("Matriz B", k, BB[k])), print(cat("Matriz D", k, DD[k]))))

But with this I end up getting this instead of what I want:

http://i.imgur.com/p087Upr.png

Any ideas are welcome, thanks in advance.

Rafael.

I found the following: 

Question:matrix multiplication element by element

Does this not apply to vectors?  If not what syntax is required?  I cannot seem to execute this simple operation which I can easily do in MATLAB.  If you have such a capability why is it not clearly documented in the HELP pages?