## 135 Reputation

13 years, 259 days

## @Carl Love  thanks for ur valuable...

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 brack...

Thanks it is the brackets[

can you please the plot3d what is the problem here.

linear_var.mw

## @  no complex number at all...

no complex number at all

## @Ali Guzel   it is run for 20 min ...

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

## @acer  thanks  do u mean&nbs...

thanks

do u mean explicit(solve(K1=0,R));

still no roots

## @Rouben Rostamian   The resean is ...

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...

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

## @tomleslie Thank you for your help....

I made changes in the Ics

 > restart: assume(x, real); assume(t, real):   sys:= { -diff(v(x,t),t)+0.5*p*diff(u(x,t),x,x)+q*u(x,t)*(u(x,t)^2+v(x,t)^2)=0,            diff(u(x,t),t)+0.5*p*diff(v(x,t),x,x)+q*v(x,t)*(u(x,t)^2+v(x,t)^2)=0         };   bc:= u(0,t) = 2,        v(0,t) = 0,        u(1,t) = 0,  # made this up        v(1,t) = 0;  # made this up   ic := u(x,0) = 4.999999999*10^9*cosh(1.414213562*x)/(3.535533906*10^9*cosh(1.414213562*x)-5.000000000*10^9),         v(x,0) = 0;   pdsol := pdsolve(eval(sys, [p=1, q=0.5]), {ic, bc}, numeric);   p1:= pdsol:-plot3d( u(x,t), x=0..1, t=0..5, color=red, style=surface, transparency=0.5):   p2:= pdsol:-plot3d( v(x,t), x=0..1, t=0..5, color=blue, style=surface, transparency=0.5):   plots:-display([p1,p2]);
 >
 (1)
 >

## pde_2022.mwI dont know what is the error...

pde_2022.mw

I dont know what is the error

Many thanks

Many thanks

## @Carl Love  here the approximation...

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 ...

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...

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
•