@Carl Love 

thanks for ur valuable comments 

I did like this

xyz := solve([a11*x+a12*y+a13*z = b1, a21*x+a22*y+a23*z = b2, a31*x+a32*y+a33*z = b3], [x, y, z]);

P1 := plot3d(eval(z, xyz[]), viewpoint = ["circleleft", frames = 20], title = "z"); plottools:-getdata(P1); A := %[-1]; mx := max(A); tr := plottools:-transform(proc (x, y, z) options operator, arrow; [x, y, z/mx] end proc); tr(P1);
becouse there is very big numbers..

if to make contours in the above plot at z=0.5

contourplot(eval(z, xyz[]), theta = .1 .. 3, phi = 0 .. 2*Pi, contours = [.5])

is it right?

linear_var.mw

@Carl Love 

Thanks it is the brackets[

can you please the plot3d what is the problem here.

linear_var.mw

@ 

no complex number at all

@Ali Guzel  

it is run for 20 min then i stop , i think that is not work

@acer 

thanks 

do u mean explicit(solve(K1=0,R));

still no roots

@Rouben Rostamian  

The resean is to find the coefficients of the Expression 

as

CoefficientList(r, (D[1](Q))(x*H2(t), H3(t)))

@tomleslie 

I change the ics to be function of x.. that is error

@tomleslie 

Thank you for your help..

I made changes in the Ics

still i had an error

Download pdeProb-2.mw

pde_2022.mw

I dont know what is the error

@acer 

Many thanks

@dharr 

Many thanks

@Carl Love 

here the approximation is real

Yp  := k -> (y[k+1]-y[k-1])/2/((1+alpha)*GAMMA(1+alpha)*h^(alpha)):Ypp := k -> (y[k+1]-2*y[k]+y[k-1])/((2-alpha)*GAMMA(2-alpha)*(h^(2-alpha))^2):

@Carl Love 

yes you are right but what can i do maybe there is somthing to do with sequence or the loop

or k from 1 to N-1 do
eq[k] := eval( ode1,
                    {x=X(k), y(x)=y[k],
                     diff(y(x),x)=Yp(k),
                     diff(y(x),x$2)=Ypp(k)} ):
    end do:

@mmcdara 

thank you very much

n(t) is real

• Do you want to plot n(t) versus t for a countable set of delta values in 3D-like representation (a solution is given below)? Yes this is the case
•  

@mmcdara 

Thanks for all the comments

 how we can plot 3d of n(t) agianst t and delta