Dear all

When I compute 
int( sin(log(x)),x=0..2) 
I obtain an exact value of the integral 
but one I compute 
int( sin(log(x+1)),x=-1..1) 
I obtain undefined integral

The two integrals are the same, using the change of variable z=x+1

Many thinks

It was interesting not to miss the solutions of such a test equation  x * (1 + 1.0001 * sin (x ^ 2)) = 0 on a fairly large arbitrary segment using NextZero.
It turned out that NextZero skips solutions.
For example, solutions in the range from 7.5 to 10 are skipped.  And two more specific solutions skipped 21.232154952 and 21.232821004.
I took Digits to help, but it didn't affect anything. Most likely the reason is that I am a bad user.  The example seems to be a good one.
 

restart: 
#Digits := 30; 
f := proc (x) options operator, arrow; x*(1+1.0001*sin(x^2)) end proc; 
RootFinding:-NextZero(f, 1.0): 
for j to 154 do RootFinding:-NextZero(f, %) end do

Dear all

I have the following proc I, I need a help so that the proc run without error. 

I get Error, invalid =

Code_eigenvalues_eigenvectors.mw

Thank you for any help 

Dear all

I run a code But I obtained the following error 

Error, (in PW) cannot determine if this expression is true or false: (1/4)*10^(1/2) < 0.1000000000e-3


and  how can I display all iterations obtained from  PW and WDEF2 in a table.

PWW.mw

Thank you for any help 

Dear all

I need to plot the solution obtained from dsolve for a system of differential equation 

plot_analytical_solution_system.mw

Thank you for any help 

How to draw a streamlines by using stream function provided in pdf. In the presence and absence of lambda parameter.

please help me to obtain graphs

1.pdf
Download 1.mw

Dear all

I compute by hand the bifurcation point of an ode, 
I fouded x=-1/2 a+ 1/2 corresponding to  h= (a+1)^2/4  with 0<a<1 

The same solution is obtained using Maple code. 
I tried to plot the birfurcation diagram to stech with kind of bifrucation ( saddle, Holf . transcritical , periodic, or someting else)
But I get 
Error, (in plots/implicitplot) invalid input: invalid range for first variable

bifurcation_diagram.mw

thank you for any help 

 

Dear all

I have a PDEs depend on u1(r,z) 
I would like to decompose u1 as sum of two function c1*r*U(z)+u(r,z) and  , where c1 is constant,  then i would like to substitute u1 in the pde by   c1*r*U(z)+u(r,z) then obtain the corresponding new equation

subs_function.mw

thank you 

Dear all

I try to understand why maple does ot plot the behavior of x^1/3 for negative real number, 

inverse_function_xthree.mw

root(x,3) is function defined verywhere, but why maple plot only this function for x positive 

thank you

Dear all

Strange phenomena...Every thing is well coded.
Using numeric solution pdsolve and  and solution based on iterative solution, gives a slighty different curve.. 

All matrices are well coded, and everything is okay... But  what happen... to get two different curves at same time.

New_code.mw

Thank you for any help 

Dear all

if I have a vector defined as u[1..11,1]:=

How can display the coeffients of  this vectors 
can I plot the vector 

Thanks for any help

dear all

I have a linear system AX=b , I would like to compute the solution using Gradient conjugate method 

CS.mw

I get the following error
Error, (in LinearAlgebra:-LinearSolve) method SparseIterative incompatible with data of type anything
 

Thank you for any help

Dear all

I would like to plot two different functions

One constructed using piecewise and second function on the sme interval. 

The code run without error but I am not sure that its true, since we have two different function but in the graph we can not see the difference betweem them 

codexsqrr.mw

Thank you for your help

Dear all
I have a problem using unapply to construct all functions defined in each intervals.
If I use unapply to construct only two peicewises fuctions the code work well, but otherwise there is someting missing 
splineProb.mw

## using code like this, its run 
ff:=unapply
                  ( piecewise
                    ( x < eval( Xlist[2], NaturalCoeffs),
                      expand( eval( S[1], NaturalCoeffs) ),
                                           expand( eval( S[3], NaturalCoeffs) )
                    ),
                    x
                  );
 

but using code like 
 

unapply
                  ( piecewise
                    ( x < eval( Xlist[2], NaturalCoeffs),
                      expand( eval( S[1], NaturalCoeffs) ),
                     ( x < eval( Xlist[3], NaturalCoeffs),
                      expand( eval( S[2], NaturalCoeffs) ),

                      expand( eval( S[3], NaturalCoeffs) )
                    ),
                    x
                  );
does not run and return 
Error, `;` unexpected
 

Thank you for your help 

dear all

I hope to write taylor expansion with remainder lagrange ..That is taylor lagrange expansion of a given function.

I tried 
series(cos(x),x=0,5) 

or taylor(cos(x),x=0,5) 
always the remainder written USING O(x^6)
I want the reminder depend on the derivative ..that is Lagrange Taylor expansion

Many thanks