In geom3d. I want to find the vertices A(x1,y1,z1), B(x2,y2,z2), where x1, y1, z1, x2, y2, z2 are integer numbers so that the triangle OAB  (O is origin) and perimeter and area are integer numbers. I tried

> resrart:

N:=5:

L:=[]:

for x1 from -N to N do

for y1 from x1 to N do

for z1 from y1 to N do

for x2 from -N to N do

for y2 from -N to N do

for z2 from -N to N do

a:=sqrt(x1^2+y1^2+z1^2):b:=sqrt(x2^2+y2^2+z2^2):c:=sqrt((x2-x1)^2 + (y2-y1)^2 + (z2-z1)^2):

p:=(a+b+c)/2:

S:=sqrt(p*(p-a)*(p-b)*(p-c)):

if type(2*p, integer) and type(S, posint)

then L:=[op(L), [[0, 0, 0], [x1, y1, z1], [x2, y2, z2]]]: fi:

od: od: od: od: od: od:

nops(L);

But my computer runs too long. I can not receive the result. How to get the answer?

If I the length of the side are 6, 25, 29. I tried 

DirectSearch:-SolveEquations([(x2-x1)^2+(y2-y1)^2+(z2-z1)^2 = 6^2, (x3-x2)^2+(y3-y2)^2+(z3-z2)^2 = 25^2,  (x3-x1)^2+(y3-y1)^2+(z3-z1)^2 = 29^2], {abs(x1) <= 30, abs(x2) <= 20, abs(x3) <= 20, abs(y1) <= 20, abs(y2) <= 20, abs(y3) <= 20, abs(z1) <= 20,abs(z2) <= 20, abs(z3) <= 20}, assume = integer, AllSolutions, solutions = 1);

Does someone know how to ask Maple to compute intersection and union of ranges (for that matter Realrange)?

Does anyone know how Maple dsolve numeric integrators with adaptive stepsize like rkf45 and dverk78 select their stepsizes? Is there anyway to find out the stepsize the procedure chooses at each step? Currently, I can only obtain the value of my solution at a particular value but I do not know how many steps Maple took and why it selected these step sizes.

if I find fourier intergra solution if 1/pi∫ （form infintiy to 0）(a*cos(u*x)+u*sin(u*x))/a^2+u^2 du. can you polt the function to the integral converges? and can you plot the fourier intergral on a=1 and -1<=x<=3 with 0<=u<=20?

if  i use a fourier transform to find an integral representation for the solution is  U(x,t)=1-1/2*erf((x+a)/(2*square rootkt))+1/2*erf((x-a)/(2*square rootkt)), can you plot the sloution on the interval -5<=x<=5 with k=10^-6 and a=1 for t=10^5 and t=10^6 , give me two graph? erf mean is  Error function !

I used implitplot to plot solutions to some (tricky) equations in 2 variables, of the form implicitplot([f(x,y)=0]).  Now I have a (tricky) change of parameterization G:R^2->R^2 of the form G(x,y)=(g(x,y),h(x,y)). I'd like to plot the image of the solution set of f(x,y)=0 under the map G. Of course, if I could invert G I'd implicitplot           G^(-1)(f(x,y))=0, but the functions I have dont lend themselves to this.

Presumably MAPLE stores the points it plots somewhere, and I should be able to apply G to this set of points. But I don't know how to approach this. Anybody know? 

Hi

Long story short I had a detailed question and then the session timed out and killed it!

Quickly then, if we calculate something recursively Maple acts differently to other languages.

For example, in Python:

__________________________________________

>>>t=1;

>>>t+=1;

>>>print t;

___________________________________________

Is interpreted as:

__________________________________________

>>>t=1;

>>>t=t+1=2

>>>print t

2

___________________________________________

In Maple:

___________________________________________

>t:=1

>t:=t+1

>print(t)

___________________________________________

Is Interpreted as:

___________________________________________

>t=1

>t=t+1=1+1=2

>print(t); t=t+1=1+1=2

2

____________________________________________
And there in lies my problem. Logically, I wish to use a iterative algorithm to work out an expression of the nth derivative of a function from the (n-1) derivative. However, doing this is in maple brings up "error (in Test) too many levels of recursion".

For context, Minimum Working Example:

____________________________________________

>TestFunction:=(x)->cos(exp(-1/x^2))*F(x):

>limit(TestFunction(x),x=0)

F(0)

>TestDerivative:=(x)->eval(diff(TestFunction(y),y),y=x):

>limit(TestDerivative(x),x=0)

D(F)(0)

>for i from 1 to 50 do
print(D^(i)(TestFunction)(0)=limit(TestDerivative(x),x=0));

TestDerivative:=(x)->eval(diff(TestDerivative(y),y),y=x):

od:

D(TestFunction)(0)=D(F)(0)

Error, (in TestDerivative) too many levels of recursion

_______________________________________________

Ideally, this code would output the limit of the second derivative at zero by differentiating the first derivative and then the limit of the third derivative at zero by differentiating the second derivative etc. But what Maple is trying to do is to find the limit of the second derivative by differentiating the function then differentiating the result of that, then to find the limit of the third derivative it will first derivative by differentiate the function, then the second by differentiating the result, then third derivative by differentiating the result of that. If I have the analytic expression for the 5th derivative and I wanted the expression for the 6th derivative, I do not want to work out the 1st, 2nd, 3rd, 4th and then 5th derivative when I've already an of the expression of the 5th derivative!

I will note, it is possible to avoid the problem by using different names at each step but that does not solve the iterative problem.  Is there anyway to force maple to overwrite a function name? Is there a seperate solution? Or is maple just that daft in this case?

Thanks for the help,

Hamzaan

3rd_order.mw This 3rd order nonlinear ode is not giving the desire result,how do I resolve it?

Thanks

I have a vector that looks like this:

"GOOG.NASDAQ_A.4"
"GOOG.NASDAQ_AAC.4"
"GOOG.NASDAQ_AACC.4"

Now in order to make the api call it has to be expressed as:

http://quandl.com/api/v1/multisets.csv?columns=GOOG.NASDAQ_A.4,GOOG.NASDAQ_AAC.4,GOOG.NASDAQ_AACC.4

or as:

"http://quandl.com/api/v1/multisets.csv?columns=GOOG.NASDAQ_A.4,GOOG.NASDAQ_AAC.4,GOOG.NASDAQ_AACC.4"


How would I make that transformation?
It looks simple but it is difficult ie string notation and you cant copy past (thousands of stocks). 

LL_101)_Quandl_Get_D.mw

I need help finding the 10th order power series and graphing it. The initial problem is x²y''+xy'+x²y=0 with initial conditions y(0)=0 and y'(0)=0. Whenever I try using dsolve({eqn, y(0) = 0, (D(y))(0) = 0}, y(x), type=series) where eqn= the initial problem, it doesn't give an output, not even an error message. And help or ideas at all would be greatly appreciated.

So i have to plot 3 ODEs. How would I go about plotting dx/dt=10(y-x) AND dy/dt=x(28-x)-y AND dz/dt= xy-8z/3. Any help at all would be appreciated.

Hi,

this question has been asked several times here already accoruding to the search function, but I didn't find an actual answer to it.

My Maple 15 gives outlarge numbers without scientific notation, so even 10^20 would be displayed as 1000....000  (20 zeroes). It seems like this is not the standard, so at one point I might have changed the way Maple displays the output, and cannot remember anymore how.

How can I tell Maple to display the output in scientiffic notation, and how can I set up the threshold of powers of ten, when this is done. (so that e.g. 100 still gets disaplyed as 100, and not as 1*10^2, but anything above gets displayed in scientific notation).

I know that I can right click on the output to change it's display form. But I want to change this generally, so I dont have to do this for any single numerical output I get.

I use Maple 15, running in Mac OS.

Thanks for help!

I have a column vector that looks like this:

"GOOG.NASDAQ_GOOG"
"GOOG.NASDAQ_AAPL"
"GOOG.NASDAQ_ZN"
"GOOG.NASDAQ_ZOOM"
....

However, I need it to be in this format:

GOOG.NASDAQ_GOOG.4,GOOG.NASDAQ_AAPL.4,GOOG.NASDAQ_ZN.4,GOOG.NASDAQ_ZOOM.4 etc

It appears to be very simple but I cant figure out how to do it in Maple.

LL_101)_Quandl_Get_D.mw

Hello everyone, I need your help again. I've been trying recently to select different colors and other line options to different curves in the 2D plot generated by the algorithm attached to this message, but I've had no success whatsoever. I tried using the setcolors([]) option, but it didn't work.

Any help with that would be much appreciated.


Link:
Equações_H,_S_e_G_(r.mw

Let a convex polygon, for example Q:=polygon([[0,2],[1,4],[4,4],[5,1],[3,0]]), be given.
How to find the rectangle of the biggest area which is contained in Q?
A procedure is required. This problem seems to be more complex than the previous one.