Hello, 

I have a PDE system. When I use pdsolve it gets me the messege " pdsolve->Warning: System is inconsistent". Is there a way I can see which equations breaks the system down? 
For this system, it's difficult to see from ayeball where the problem is. 
Thank you! 

test.mw

Hello

Unfortunately I got stuck again when trying to work with monomials.  Consider the following set of set of monomials:

f := [theta[1]*y+theta[2]*z,theta[3]+theta[4]*x+theta[5]*y+theta[6]*z+theta[7]*x*y+theta[8]*x*z+theta[9]*y*z,theta[10]*x+theta[11]*y+theta[12]*z+theta[14]*x*y+theta[15]*x*z+theta[16]*y*z+theta[17]*x^2+theta[18]*y*y+theta[19]*z*z+theta[20]];

x, y and z are the variables and thetas are the coefficients.  The coefficients theta can be zero and I need to classify the resulting set as valid or not.   Here are some examples of not valid sets

fff:=[theta[1]*y+theta[2]*z,theta[5]*y,theta[10]*x+theta[11]*y+theta[12]*z+theta[14]*x*y+theta[15]*x*z+theta[16]*y*z+theta[17]*x^2+theta[18]*y*y+theta[19]*z*z+theta[20]];

ffff:=[theta[1]*y+theta[2]*z,theta[5],theta[10]*x+theta[11]*y+theta[12]*z+theta[14]*x*y+theta[15]*x*z+theta[16]*y*z+theta[17]*x^2+theta[18]*y*y+theta[19]*z*z+theta[20]];

fffff :=[theta[1]*y+theta[2]*z,theta[3]+theta[4]*x+theta[5]*y+theta[6]*z+theta[7]*x*y+theta[8]*x*z+theta[9]*y*z,theta[12]*z+theta[19]*z*z+theta[20]];

that is, the first coordinate of the set cannot be a function of x alone, the second coordinate cannot be a function of y alone and the third coordinate cannot be a function of z only.  

I could not figure out how to do that automatically, can you help me, please?

Many thanks.

When I use the Determinant function on a matrix with (single variable) polynomial entries with real coefficients I often get an incorrect answer. I know the answers are incorrect because they have a higher degree or a lower lowest degree than is possible given the matrix elements.

However, when I replace the coefficients in the polynomials with rational numbers or I put in the option method=minor, I get the correct answer.

The problem seems to be roundoff error. However, the important error is not simply small changes in the resulting polynomial. The important error is the presence of entirely incorrect powers of the variable and not with very small coefficients.

How does this happen and why does the help page for Determinant( ) not warn of this behavior? In particuiar, why does the help page not say that using Gaussian elimination (i.e., the default) will often give incorrect answers in such cases, but using method=minor will work? Is this behavior known? I cannot find any reference to it on the internet.

Hello all. Is there any solution for the indefinite integralBadIntegral.mw

Download BadIntegral.mw

?

Thanks

i copy maple code from notepad to maple in maple window,

there is no error

my function in the code

explicit define parameters are Local type

for example

appendto("...");

func1(aaa)

Local aaa;

but when i run cmaple to read the code text file in window 8

it return error

missing operator, syntax error

at Local aaa;

originally 

i have defined

Local aaa, ii;

for ii from 1 to nops(aaa) do

etc.

but it has error too,

then i change to one by one

Local aaa;

Local ii;

still have error at Local aaa;

if i m working in maple 13 i have to solve a non linear integral equation then what will be the steps to use the do loop.

How does one obtain all solutions from dsolve? I see an option called Allsolutions, but this seems to only apply to solve and other functions. It does not work with dsolve.

For example, maple gives one solution for the following first order non-linear ODE. But the ODE has another solution y(x)=0 as well. How does one tell Maple to return all solutions? I am interested in this when using the 'implicit' option mainly. Here is an example

restart;
num:=-(exp(x)*sin(y(x))-2*y(x)*sin(x)):
den:=(exp(x)*cos(y(x))+2*cos(x)):
eq:=diff(y(x),x)=num/den;

r0:=dsolve(eq,y(x));

But when I tried y(x)=0, it turned out to also be a solution

odetest(y(x)=0,eq);
                          0

But dsolve did not return this solution on its own along with the first one.  But on another example, Maple did well, and returned all solutions. Here is the other example

eq:=(2*x*y(x)^2+2*y(x))+(2*x^2*y(x)+2*x)*diff(y(x),x);
dsolve(eq=0,y(x),'implicit');

In the above, Maple returned the two solutions. 

Is there a correct way to tell Maple dsolve to return all solutions all the time? Why did it return both solution in the above example, but not in the first example?

I am maple newbie. Thank you.

hi

how i can draw this equation in maple in 3D?

(x-y)^2+(x-z)^2+(z-x)^2=3

thanks

PLOT3D.mw

I'm modeling the interaction between rotation and vibration in water molecule. I've come up with the solution functions, but I wanted to make some illustrative animations to fully understand what is going on. I made an animation (in the very end of the attached file) showing vibration of molecule and I want the trajectory of each (of two) particles to be traced after it, how could it be done? Also I want to have the movement of the angular momentum vector (vector with components [Jx=J*cos(varphi)*sin(theta), Jy=J*sin(varphi)*sin(theta), Jz=J*cos(theta)]) be animated simultaneously with the vibration of molecule (on the same plot). Is it hard to achieve?

File: ClassicalTrajectoriesH2X_morse.mw

Hello all,

Is here anyone who could help me with this Integral.

I want to determine P(y=2) in which the Nu is a constant and also is unknown.

In deed I want to derive the P which only has one unknown parameter(Nu). But I cannot solve this indefinite integral although the \alpha_1 , \alpha_2 and B are known constants. The Nu parameter mustn't be valued preferely.Indefinite_INtegral.mw

> restart;
> with(plots);
> setoptions(title = `Family Plot`, axes = boxed);
> pr := .71; n := 1; p := 0; q := 0; b := 0; l := 0; s := 0; m := 0;
>
>
> R1 := 2.*n/(1+n);
                                 1.000000000
> R2 := 2.*p/(1+n);
                                     0.
> sol1 := dsolve([diff(diff(diff(f(eta), eta), eta), eta)+f(eta)*(diff(diff(f(eta), eta), eta))+R1*(1-(diff(f(eta), eta))^2) = 0, diff(diff(theta(eta), eta), eta)+.71*f(eta)*(diff(theta(eta), eta))-.71*(diff(f(eta), eta))*theta(eta)*R2 = 0, f(0) = 0, (D(f))(0) = 1.8+b*((D@@2)(f))(0), (D(f))(18) = 0, theta(0) = 1+s*(D(theta))(0), theta(18) = 0], numeric, method = bvp[midrich]); plots[odeplot](sol1, [eta, theta(eta)], color = red, axes = boxed);

Dear sir/madam

In my program i want to plot multiple lines for diffrent values of n, but i do not have such type of idea please can you help me.

Hello there. I have to solve a simple line integral (3*y-x)dL from A(2;1) to B(3;-1). A and B are points in the line described by function y=5-2x. I found a function LineInt. Using paramether Line I wrote LineInt(3*y-x, Line(<2, 1>, <3, -1>)), it doesn't work with error below:

Error, (in Line:-ModuleCopy) invalid input: invalid specification of line

It seems that the problem is with first argument, that is the equation under the integral sign. Or no... How to write it properly? Thanks.

Here is my code. I am deriving soil compression line for oedometric testing with porosity, below is a part of the derivation.

I would like to differentiate the (Sst/Vst)/(Spt/Vpt) by dsm first then integrate it with dsm ranges from 0 to dmax to get my final answer...

Hope someone can help me on writing the code... Thank you very much!!!

Download GEO_Assignment_3.mw