Hi,

I've been playing around with the Physics package, and I'm confused on evaluaing derivatives of explicit funcitons of the coordinates. This code below doesnt behave as I would think. I'm trying to define z as a function of X[mu]*X[mu], and take diff(z, X[mu]). You can see that each method d_, diff, disagree and none are satisfactory ansers. (Maple 2015, Windows 8.1 64-bit, Intel i5 Haswell)

# Declare coordinates for 2 dimensions, flat space

restart:with(Physics):Setup(mathematicalnotation = true, dimension = 2):Coordinates(X):# Method 1: Using Define and various differential operatorsDefine(z):z :=sqrt(R^2-X[mu]*X[mu]);d_[mu](z(X)); d_[1](z(X)); diff(z, x1); #This one is correctdiff(z, X[mu]); # off by 2

# Method #2: Using functions# Off by a factor of 2z2 := mu -> sqrt(R^2-X[mu]*X[mu]);diff(z2(mu), X[mu]); # off by 2

PhysicsDiffBug.mw

In the following, the diff operator calcuates the derivative correctly, but the D operator doesn't. A bug?

restart;

f := x -> a[1][2]*x; # the double index on a[][] is intended

diff(f(x), x);

D(f)(x);

Here is a worksheet containing the commands above in case you want to try it yourself: mw.mw

Hi all,

It's been a while since I have used Maple. To be honest I haven't used it for over six years.

I am trying to solve simple differential equations, however I have many issues.

I am trying to simulate what author of this paper did 06421188.pdf

My file looks like this (Pendulum.mw)

Can someone help me to simulate this system? I simply can't remember how to do it.

Cheers,

Bart

I have the following :

with(powseries):difeq:=diff(y(x),x,x)+x*y=0;icval:=y(0)=1,D(y)(0)=0;pow_soln:=powsolve({difeq,icval});tpsform(pow_soln,x,30);pow_soln(_k);

for which the transformed power series

is : 1 -(1/6)y*(x^3)

and pow_soln(_k) returns 0. What does this mean?

****** My question *****

for k from 0 to n do # n is any integer.

func := f(x): # func is any funciton of x.

D := diff(func, x$k); # The maple don't allow to uses k but I want to diff k-th order in each k-loop.

end do; # How to diff func for k-th times in each k-loop.

I have a nice family of functions of the form:

W:=(p,n,mu,w)->sum(w[k] * (n-k)^{p *} mu^{(n-k)},k=1..n)

which can be evaluated for different p's using the operator mu*diff(...,mu)

The recursion begins with p=0 and proceeds using mu*diff(W(p,n,mu,w),mu) = W(p+1,n,mu,w).

Can anybody implement this procedure in Maple

Thank you

I've got the following piecewise function :

(x^2+y^2)^(alpha).arcsin(y/x) if (x,y) are in [-pi/2,pi/2]

0, (x,y)=(0,0)

1. How do I plot this function taking the alpha variable and the piecewise construct into account?

2. How can I check for points of discontinuity, indifferentiability from the plot/function itself?

I've got a function y(x) that is initially defined as x^3+y^3=1 and need to plot it, and find y',y''.

At present, I've used implicitplot(x^3+y^3=1,x=0..5,y=0..5) to plot it, but that doesnt seem to work. Also, to find y'

I've used the statement

implicitdiff(g(x,y),y(x),x) where g:=(x,y)->x^3+y^3=1 but this gives me an error that my input is invalid; y(x) is expected to be of the form {(name, set(name), set(function(name))}.

I don't quite understand..

I am new to Maple. I am working though the manual and in chapter two I tried to get the derivative of ln(x^2+1). I am getting something completely different that the actual derivative. I tried a simple derivatie (the derivative of 2x and get 0). I do not know what I am doing wrong. Any help will be appreciated.

The link to the .mw file is underneath the content.

I was trying to solve the first order ode for x(t). pp1 and pp2 are essentially diff(x(t),t).

I just wanted to see them plottet. While deriving these equations (which stem from a first order nonlinear quadratic diff. eq.) I had to distinguish between those 2 solutions. Also I made the assumption that diff(x(t),t) everywhere so the only solution being allowed should be pp1. Oddly the analytic solution for pp2 looks like the numeric solution for pp1 and my question is: Why is that?

Warning, computation interrupted

Download rutschender_Stab.mwrutschender_Stab.mw

I am trying to solve the following differential equation numerically using dsolve,

y * abs (y''') = -1

y(0) =1, y'(0) = 0, y''(0)=0

it works fine when tthe absolute function is not there, i.e. yy''' = -1.

Do you have any suggestion?

I am also not sure how to program a check in the code to determine that dsolve solved the differential equation.

For example

ode:=diff(y(x),x)-a*(x^n-x)*y(x)^3-y(x)^2=0;sol:=dsolve(ode,y(x));

In this case, sol is () as it could not solve it. When I tried odetest, I get an error

odetest(sol,ode);

Error, invalid input: odetest uses a 2nd argument, ODE, which is missing

What is the correct way to check dsolve was successful that will work for all cases? I am looking for programmable method, no GUI use.

Hello,

I am trying to solve the boundary value problem (1-x^2)*y'' - 2*x*y' +12*y = 0 with y(-1) = -1 and y(1) = 1. I have not used Maple much, but from some web surfing, it seems like the following inputs should work:

de := (1-x^2)*(diff(y(x), `$`(x, 2)))-2*x*(diff(y(x), x))+12*y(x) = 0

Y := dsolve(de, y(-1) = -1, y(1) = 1)

However, when I input these lines, I get the error: Error(in dsolve), found wrong extra argument(s): y(-1) = -1, y(1) = 1

Does this mean that Maple can't solve this problem? Is my syntax wrong? I would appreciate any help.

Thanks!

Tim

I have a long expression with different order derrivatives, that is written in form like that:

-(D[1](f))(x, y)

I'd like to transform it into standard maple form like:

Is there any special procedure to achieve this goal?

Hi every body:

i will earn the cofficients of q(T),q(T)^2 and (diff(q(T), T, T)) with commonds maple,how?

eq := 324.6463527*(diff(q(T), T, T))+4.012505275*10^11*q(T)+3.589858529*10^12*q(T)^2 = 0;

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