## how can I solve (Error, unable to compute coeff) e...

I get error on Maple code

N := 4

f(x):=sum(p^i*fi, i = 0 .. N);

HPMEq := (1-p)(diff(f(x), x$3))+p(diff(f(x), x$3)+(1/2)(diff(f(x), x, x))*f(x));

for i from 0 to N do equ[2][i] := coeff(HPMEq, p, i) = 0 end do

Error, unable to compute coeff

## Solving the time independent schrodinger equation...

I'm trying to solve this schrodinger equation for a quantum oscillator:

E = n + 1/2 where n = 0,1,2,3,4

If I just use dsolve then I get a bunch of Bessell functions and I'm not sure why.

Can anyone point me in the right direction?

Thanks.

## Definite Integral...

How can I analytially evaluate the following definite integral ?

int(1/(c*x + d), x = a .. b)

My Output is as follows:

Thanks.

## is there any library or tools to design index of G...

is there any library or tools to design index of Grassmannian and its k and n for Schubert use?

is there any library to relate poset with index of Grassmannian and its k and n for Schubert use

## Dimensions disagree... no they don't ;/...

RandomMatrix(n, 1);

does not seem too work with Vectors of dimension d in elementwise multiplication ;/ Even though it is an nx1 matrix = an n vector.

This seems like a limitation maple!

RandomVector(n);

Does seem to work with Matrix and Vector.

Matrix(5,1)*~Vector(5);

Both have the same dimensions and should be possible to multiply them pointwise!

## Why does my procedure not work?...

with(RegularChains);
R := PolynomialRing([x, y, z]);
p1 := x^2+5-2*x*z;
p2 := z^3*y+x*y^2;
p3 := -8*z^3+3*y^2;
F := [p1, p2, p3];
MainVariable(p1, PolynomialRing([x, y, z]));
MainVariable(p1, PolynomialRing([z, y, x]));
prem(p1, p2, x);
prem(p2, p1, z);
prem(p3, p2, y);
premcustom := proc(Fparam,Gparam, xparam)
local R, G, F, lcg, lcr, dr, dg:
R := Fparam:
G := Gparam:
F := Fparam:
if degree(G,xparam) = 0 then
print("return 0"):
return 0:
elif degree(F, xparam) < degree(G, xparam) then
print("return R"):
return R:
else
lcg := coeff(G, xparam, degree(G, xparam)):
dg := degree(G, xparam):
while degree(R, xparam) > degree(G, xparam) do
lcr := coeff(R, xparam, degree(R, xparam)):
dr := degree(R, xparam):
R := lcg * R - lcr * G * (x^(dr - dg)):
od:
end if:
return R:
end proc:
coeff(p1, x, degree(p1, x));
coeff(p2, x, degree(p2, x));
prem(p1,p2,x);
prem(p2,p1,z);

premcustom(p1,p2,x);
premcustom(p2,p1,z);

why premcustom looping?

is this coeff(p1, x, degree(p1, x)); wrong ?

should this to get real coefficient in number instead of variable and how?

is there equivalent function as dprem?

with(diffalg):with(diffalg):
FlessThanG := proc(Fparam, Gparam, PRing)
F := Fparam:
G := Gparam:
return True:
else
return False:
end if:
end proc:
dprem := proc(Fparam, Gparam, x, PRing)
local R, theta, thetax, thetaG, F, G;
F := Fparam:
G := Gparam:
R := F:
while FlessThanG(R, G, PRing) or FlessThanG(G, R, PRing) do
R := prem(R, thetaG, theta)
od:
return R:
end proc:
R := differential_ring(ranking = [[x,y,r]], derivations = [t], field_of_constants=[m,l], notation = diff):
p1 := m*x[2] + r*x;
p2 := m*y[2] + r*y - g;
p3 := x^2 + y^2 - l^2;
dprem(p1, p3, x, R);

is x[2] = diff(x,t\$2) in diffalg ?

if not how to write in this way?

but got error

Error, (in DifferentialAlgebra:-Tools:-LeadingDerivative) unknown symbol (approx. error location: [m*x[2 --> ] <-- +r*x])

## search for a function that can do convolution...

Hello, everyone,I can not find a function that can do convolution, so if you know please tell me. Thanks!

## Taylor Series of Nonlinear Function ...

what is the Taylor Series of

F(x,y+q,G(x+q,z) )

where x,y,z is variables and q is constant

## obtain the second-last result ...

Just a quick question, I know we can use "%" to obtain the las result in maple. what if I want to obtain the second last result? or in general the n-last result ? Thx

## PDEs boundaries...

Hi, I'm trying to solve 1-D thermal equation defined below, but I end up with an error : Error, (in pdsolve/numeric/process_PDEs) PDEs can only contain dependent variables with direct dependence on the independent variables of the problem, got {f(t, 1)}.

Could you please point out what am I doing wrong? Perhaps it's how I define the PDe or how I write the boundaries? Any help appreciated!

with(PDEtools)

PDE := cp*diff(T(t, r), t) - k_1*diff(diff(T(t, r), r), r) - k_1*diff(T(t, r), r)/r = Q;

all variables for now have dummy values of 1

cp := 1;
k_2 := 1;
A := 1;
k_3 := 1;
k_4 := 1;
k_5 := 1;
k_6 := 1;
T_amb := 1;

bcs_1 := eval(diff(T(t, r), r), r = 1) = k_3*T_amb;

bcs_2 := eval(diff(T(t, r), r), r = 0) = 0;

bcs_3 := eval(diff(T(t, r), t), t = 0) = 25;

PDE_all := {PDE, bcs_1, bcs_2, bcs_3};

sol := pdsolve(PDE_all, numeric);
Error, (in pdsolve/numeric/process_PDEs) PDEs can only contain dependent variables with direct dependence on the independent variables of the problem, got {f(t, 1)}

## Int not working ...

Int not working with GlobalSolve why? It shows that bounds should be specified to all variable. but i have given bounds to all variables already. Thank you

## How do I solve an over determined system of algebr...

How do I solve an overdetermined system of algebraic equations in Maple? solve command returns trivial solution for variables which are not actually trivial when I solve them by hand.

## differentiate piecewise constant function...

Hi all

When I solve using maple the first-order differential equation: diff(y,x)=0  for x in the closed interval [0,1] we obtain a constant function as a solution

but one can define the piecewise constant function see please the attached code

diff_piecewise.mw

why when we differentiate the piecewise function gives undefined derivative at point zero and a half.

Whats is the relationship between this example and Existence and uniqueness theorem for fist order ode

Many thanks

## Is there a way to solve numerically a system of in...

Hello everybody,

While i was trying to work on a physical math problem, a system of 4 integral equations is obtained. The right hand sides of these equations are known functions of r. The left hand sides contain double integrals with respect to lambda and t. i believe that an analytical determination of the 4 unknown functions f_1(t), f_2(t), f_3(t), and f_4(t) is far from being trivial, thus recourse to a numerical technique is necessary and indispensable.

i tried to express the unknown functions as series expansions in t and solve the resulting linear system of equations for the expansion coefficients, but unfortunately the coefficients are very large and the solution is strongly dependent on the number of coefficients. i was wondering whether someone here has some experience with such integral problems and is willing to assist and help. Any hint is highly appreciated.

i attach a Maple script including the equations.

Thank you,

>>>>>> Question.mw

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