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WA573

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2 years, 131 days
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These are questions asked by WA573

Error, (in PDEtools/Normal) invalid inpu...

WA573 80 Maple 2022
simplification
November 18 2022
1 2

Why is the Maple giving this error. See attched file. Further, how can we eq. of the form "A+B`*sqrt(C) = 0" by eliminating the common denominator.

CM_TW.mw

Why Maple returns empty solution?...

WA573 80 Maple 2020
syntax 2dmath pde
November 15 2022
1 2

Why Maple returns empty solution (see eq. (5))? Also, is it possible that Maple not only gives us the explit solution but also the solution steps?

> 

restart
> 

with(PDEtools, TWSolutions, declare)

[TWSolutions, declare]

 (1)
> 

with(DEtools, diff_table)

[diff_table]

 (2)
> 

U := diff_table(u(x, t))

table( [( ) = u(x, t) ] )

 (3)
> 

sys := {U[]*U[x]+U[t]-pU[x, x]+qU[x, x, x] = 0}

{u(x, t)*(diff(u(x, t), x))+diff(u(x, t), t)-pU[x, x]+qU[x, x, x] = 0}

 (4)
> 

TWS_sol := TWSolutions(sys)

(5)
> 

map(pdetest, [TWS_sol], sys)

[]

 (6)

``

Download twsol.mw

How can we determine the highest (or pea...

WA573 80 Maple 18
maximize plotting
November 07 2022
1 2

How can we determine the highest (or peak) value for every hump and at what value of (x, t) in the plot?

peak.mw

finding the dispersion relation...

WA573 80 Maple 18
homework pde pdsolve
October 28 2022
1 1

How to find the dispersion relation (3) in Maple? I try it by equating the coefficients of cos(kx + wt) and its derivative to zero, but couldn't find it.

> 

restart
> 

with(LinearAlgebra):
> 

alias(E = E(x, t), P = P(x, t), N = N(x, t), Q = Q(x, t));

E, P, N, Q

 (1)
> 

d := Matrix([[c*(diff(E, t))+diff(E, x), alpha*P, 0, 0], [N[0]*E, diff(P, t), -sigma[2]*Q[0]*N/N[0], sigma[2]*omega[0]*Q], [0, sigma[1]*sigma[2]*Q[0]*P/N[0], diff(N, t), 0], [0, -omega[0]*P, 0, diff(Q, t)]]) = 0

d := (Matrix(4, 4, {(1, 1) = c*(diff(E(x, t), t))+diff(E(x, t), x), (1, 2) = alpha*P(x, t), (1, 3) = 0, (1, 4) = 0, (2, 1) = N(x, t)[0]*E(x, t), (2, 2) = diff(P(x, t), t), (2, 3) = -sigma[2]*Q(x, t)[0]*N(x, t)/N(x, t)[0], (2, 4) = sigma[2]*omega[0]*Q(x, t), (3, 1) = 0, (3, 2) = sigma[1]*sigma[2]*Q(x, t)[0]*P(x, t)/N(x, t)[0], (3, 3) = diff(N(x, t), t), (3, 4) = 0, (4, 1) = 0, (4, 2) = -omega[0]*P(x, t), (4, 3) = 0, (4, 4) = diff(Q(x, t), t)})) = 0

 (2)
> 

> 

re := -c*omega^3-kappa*omega^2+(c*omega[0]*(N[0]^2*sigma[2]+Q[0]^2*sigma[1])/N[0]^2-alpha*N[0])*omega+kappa*omega[0]*(N[0]^2*sigma[2]+Q[0]^2*sigma[1])/N[0]^2 = 0;

-c*omega^3-kappa*omega^2+(c*omega[0]*(Q[0]^2*sigma[1]+N[0]^2*sigma[2])/N[0]^2-alpha*N[0])*omega+kappa*omega[0]*(Q[0]^2*sigma[1]+N[0]^2*sigma[2])/N[0]^2 = 0

 (3)
> 

``

``

Download d_relation.mw

Warning, unable to evaluate 2 of the 6 f...

WA573 80 Maple 2020
numeric plotting
October 14 2022
2 2

"Warning, unable to evaluate 2 of the 6 functions to numeric values in the region; see the plotting command's help page to ensure the calling sequence is correct" How to fix it?

mww.mw

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