## undefined and defined at the same time...

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

## NextZero and a simple example...

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```

## Error, invalid =...

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

## flotting point : cannot determine if this express...

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

## plot solution of system of differential equation ...

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 streamline by using stream function ...

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

## bifurcation diagram plot ...

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

## substitute function in PDEs...

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

## root(x,3) behavior ...

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

## pdsolve and iterative gives slight different curve...

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

## display vector from storage rectangular ...

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

## Iterative solution ...

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

## Plot two different funcitons...

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

## unapply to define piecewise function...

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

## Remainder Lagrange in series ...

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

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