## Solving a trivial pde in Maple 20018...

Hi everybody,

Im trying to solve the following trivial pde using Maple 2018

pdsolve([diff(Y(x, t), t, t) = 0, Y(x, 0) = 0, (D[2](Y))(x, 1) = 0]);

Obviuosly the solution is Y(x, t) = 0, but Mapple 2018 is not giving any answer.

This works in Maple 2015.

Why is not working in Maple 2018?

Thanks,

Javier

## Error in rootfinding...

Hello,

Error, (in RootFinding:-Analytic) Maple was unable to allocate enough memory to complete this computation.  Please see ?alloc

What should I to do to overcome this error?

## How do I sovle Double integration of function cont...

restart;

##########  omega and theta are variables,where J[3],F[2],H[2],etc are constants.

t1:=-1/(-16.*omega^2+exp(-4*omega)+exp(4*omega)-2.)*(-(0.5817764173e-1*I)*exp((2/9)*omega*cos(theta))*omega^5*cos(theta)*J[3]-(.6981317009*I)*exp((2/9)*omega*cos(theta))*omega^4*cos(theta)*H[3]-0.4524927691e-1*exp(.2222222222*omega*(cos(theta)-9.))*cos(theta)*omega^3*G[3]-.6205615118*exp(.1111111111*omega*(2.*cos(theta)-9.))*cos(theta)*omega^3*H[2]+.6205615118*exp(.1111111111*omega*(2.*cos(theta)-9.))*cos(theta)*omega^3*F[2]+.9308422676*exp(.2222222222*omega*(cos(theta)-9.))*cos(theta)*omega^4*H[3]-.1034269187*exp(.1111111111*omega*(2.*cos(theta)-9.))*cos(theta)*omega^3*G[2]-0.7757018900e-1*exp(.1111111111*omega*(2.*cos(theta)-9.))*cos(theta)*omega^2*G[2]-0.7757018898e-1*exp(.2222222222*omega*(cos(theta)-9.))*cos(theta)*omega^4*J[3]-0.9696273622e-1*exp(.2222222222*omega*(cos(theta)-9.))*cos(theta)*omega^3*J[3]-0.4524927691e-1*exp(.2222222222*omega*(cos(theta)-9.))*cos(theta)*omega^2*J[3]-.2714956613*exp(.2222222222*omega*(cos(theta)-9.))*cos(theta)*omega^2*H[3]-0.7757018898e-1*exp(.2222222222*omega*(cos(theta)-9.))*cos(theta)*omega^4*G[3]+0.8726646261e-1*exp((2/9)*omega*cos(theta))*omega^3*J[3])*cos((2/9)*omega*sin(theta));

t2:=int(int(t1,omega=0..infinity),theta=0..2*Pi);

## Zeros of analytic function...

Dear Sir,

I have a question: I have an analytic function depending on a real parameter that is of the form  F_y (z) with y>0 and z is complex.

I search the zeros  of F_y(z), that is the complex z staisfying F_y(z)=0. I used  the Maple function

RootFinding:-Analytic(F, z, re = -5 .. 0, im = -100 .. 100, );

but he displays me an error message  "Error, (in RootFinding:-Analytic) the function, -(100+I*z)^(1/2)*(80-I*z)^2*cosh((1/150)*(100-I*z)^(1/2)*Pi)*sinh((1/150)*(100+I*z)^(1/2)*Pi)+(100-I*z)^(1/2)*(80+I*z)^2*cosh((1/150)*(100+I*z)^(1/2)*Pi)*sinh((1/150)*(100-I*z)^(1/2)*Pi)+(2*I)*y*z^2*cosh((1/150)*(100-I*z)^(1/2)*Pi)*cosh((1/150)*(100+I*z)^(1/2)*Pi), depends on more than one variable: {y, z}. "

Can you help me to resolve my problem?

Best regards,

Zayd.

## Solving simultaneous equations and forcing Maple t...

Hi,

I am trying to find p and q from this simultaneous equation as a function of system parameters. I do not know the parameters and I need an expression. But Maple simply just gives p=0 and q=0 as an answer

Eq1:=61*q*L__1^2*C*e*eta/(16*omega__n^2)+5*q*L__1^2*C*e^3*eta^3/(8*omega__n^4)+3*C*p^3*gamma__1*(1/4)+3*q*C*p^2*R__n/(4*omega__n)+q*L__1^2*C*e^4*eta^4/(16*omega__n^5)+145*q*L__1^2*C/(64*omega__n)+3*q^3*C*R__n/(4*omega__n)+3*p*C*q^2*gamma__1*(1/4)+q*R*C/(4*omega__n)+19*q*L__1^2*C*e^2*eta^2/(8*omega__n^3):
Eq2:=-3*C*p^3*R__n/(4*omega__n)-3*p*C*q^2*R__n/(4*omega__n)-p*L__1^2*C*e^4*eta^4/(16*omega__n^5)-5*p*L__1^2*C*e^3*eta^3/(8*omega__n^4)-19*p*L__1^2*C*e^2*eta^2/(8*omega__n^3)-61*p*L__1^2*C*e*eta/(16*omega__n^2)-145*p*L__1^2*C/(64*omega__n)-p*R*C/(4*omega__n)+3*q*C*p^2*gamma__1*(1/4)+3*q^3*C*gamma__1*(1/4):
sys := { Eq1 , Eq2 };solve( sys, {p,q} );


Is there any way to help Maple to try other conditions, I know the only solution should not be just p=0 and q=0.

Thanks,

Baharm31

## Unapply versus arrow operator...

Hi,

I do not really understand the difference between annrow operator and unapply.
From the help pages it seems that unapply "creates" an arrow operator and thus that they could be two different ways to do the same thing.

restart:

f := x[1]+y[1]:

a := indets(f):                  # just because f can be more complex than the f above
g := (op(a)) -> f;              # generates an error, "operators not of a symbol type"
h := unapply(f, (op(a)))   # ok, but with a strange output
h := (x__1, y__1) -> x__1+y__1

So it seems that Maple has transform by itself the indexed x[1] and y[1] into symbols x__1 and y__1.

Could you explain me what happened exactly ?

TIA

## How to tell Maple to give the highest order of der...

Assume we have an expression in several variables, x,y,z,..., where all of them are function of one parameter, t, for an example consider the following simple expression;

try2.mw

## use factor or using rule for simplify...

How I can simplify result? For factor or using rule.

Thanks

## Problem changing signature in Physics package...

Hello,

I am trying to work with the Physics package to calculate Christoffel symbols. I have just started using Maple today and am coming up against a few hurdles.

I want to change the signature of the metric from (+---) to (-+++). I am typing the following in math mode:

Setup( signature = '-+++')

However, this is returning the following error:

"Error, invalid sum/difference" with my command rewritten within a red box together with the last '+" within another red box. Can you please help me out with this?

Thank you.

## Error, unterminated loop...

Hello,

How can write a code for determination of Laplacian in a new form is introduced in maple code (First line).

Thank you.

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