Hello people in mapleprimes,

To the following expression, I want to apply applyop so that I want to change its denominator expanded ,

but I don't know how to do it.

So, I am writing now hoping someone  teach me it.

m:= 2*p/(p^2+1)^2;

op(m) brings the result of 2, p, 1/(p^2+1)^2,

And, op(1,m) is 2, op(2,m) is p and op(3,m) is 1/(p^2+1)^2, and

op([3,1],m) is p^2+1 and op([3,2],m) is -2.

So, the tree is `*`{2,p, 1/(p^2+1)^2}, and the tree of 1/(p^2+1)^2 is `^`{p^2+1,-2}.

And, the command expand can't play that rule on 1/{(p^2+1)^2} as its original rule is

to expand the mere numerator. And, anyway, 1/{(p^2+1)^2} is interpleted by maple as (p^2+1)^(-2),

which is not 1 devided by (p^2+1)^2, the latter of which is seen to be expanded to be p^4+2*p^2+1, but

the interpletation by maple of it is not so, and if applyop(`denom`,expand,m) works, even it is good.

But, it doesn't follow the syntax of maple. Then, can't use applyop in this case?

Best wishes.

taro

hi.

i have problem with this eq.

i need your help.

Cant plot this graph. pls help

Noah-Kazeem_real_tetta_graph.mw

Hello,

I'm stuck with maple 2016 as it crashes after a few minutes use.

it did work for a few weeks. It appears that its java crashing,

ive been given no error code or anything. uninstalling java and reinstaling did work.

im running the proper bit version. (64) rollio

tried backrolling windows, didnt work.

tried running it as Administrator no luck, ran it on backward compatibility windows 8 and 7. 

ive run out of ideas the last option seems to be a clean windows install.

any help would be greatly appreciated.

the laptop in question (HP notebook 15-ba005no)

runs windows 10 (64bit)

8gigs of ram

cpu AMD E2-7110 1.8 GHz

128 GB SSD

gpu amd radeon r2

thanks in advance. 

dkdwarf.

Hello,

I've got the following problem: Sometimes when I let Maple compute an integral it gives a result which is much smaller than it should be. This happens even for rather simple integrals such as the product of a Gauss function and a 1/x-type function. Here's a minimal working example:

restart;
with(plots):
f := x -> exp(-x^2):
g := (x,a) -> 1/(1+abs(x-a)):
plot([f(x),g(x,3)],x=-3..10):
for a from 1 to 100 do
A[a] := int(f(x)*g(x,a),x=-infinity..a-1)
end do:
B:=[seq(A[a],a=1..100)]:
X:=[seq(a,a=1..100)]:
plot(X,B);

The plot it returns looks like this:

which is clearly wrong between around a=35 and a=60...

Does anyone have an idea how this can be repaired?

Hello,

I try to use the Explore function on a trigonometric expressions depending of 8 parameters. My aim is to study the influence of these parameters on the results.

However, i receive an error message and I didn't manage to troubleshoot it.

May you have a look of an extract of my code and see if you see the mistake ?

TestExplore.mw

Thanks a lot for your help.

Dear sir

I try the below program and it is not executing because of error and that error is " unable to match delimiters" 

Please can you varify it.

sol1 := dsolve([diff(diff(diff(f(eta),eta),eta),eta)+f(eta)*diff(diff(f(eta),eta),eta)+((2*n)/((n+1)))*(1-diff(f(eta),eta)^2) = 0, 1/(Pr) *diff(diff(theta(eta),eta),eta)+f(eta)*diff(theta(eta),eta)-((2*p)/((n+1)))diff(f(eta),eta)*theta(eta) = 0, f(0) = 0, D(f)(0) = 1+lambda*'@@'(D,2)(f)(0), D(f)(10) = 1, theta(0)=0, theta(0)=1+sigma*D(theta(0)),theta(10)=1], numeric, method = bvp);  plots[odeplot](sol1, [eta, `@@`(D,2)(f)(eta)], color = red,axes=boxed);

Dear Community,

Is there an explicit command to remove rows or columns from a DataFrame? I've only found the Append command. What's the easiest way to do it?

Tx in advance,

best regards

Andras

eq2 := -4*A[2]*cos(2*x)-16*A[4]*cos(4*x)-36*A[6]*cos(6*x)-64*A[8]*cos(8*x)+a*A[0]+cos(8*x)*a*A[8]+cos(6*x)*a*A[6]+cos(4*x)*a*A[4]+2*cos(2*x)*q*A[0]+cos(2*x)*a*A[2]+q*A[8]*cos(6*x)+q*A[8]*cos(10*x)+q*A[6]*cos(4*x)+q*A[6]*cos(8*x)+q*A[4]*cos(2*x)+q*A[4]*cos(6*x)+q*A[2]*cos(4*x)+q*A[2]

How to extract the co-fficent that do not have cos in it like

a*A[0]+q*A[2]

Dear all

I have a PDE and its analytical solution. I want to find the numerical solution by Finite Difference Method.

I duscratize the PDE and boundary condition and Could not able to solve them togethe.

Here is the file FEM-Nu.mw

of the implicit function sin(x+y)+sin(x) = y at x = Pi , y=0 of order 15? Here is one of the difficulties

restart; eval(implicitdiff(sin(x+y)+sin(x) = y, y, x$15), [x = Pi, y = 0]);
Error, (in expand/bigprod) Maple was unable to allocate enough memory to complete this computation. Please see ?alloc

Hi everybody,

I solve an ODE system numerically with the command

Tend := ….. :
sol := dsolve(MySys, numeric, method=rosenbrock, range=0..Tend):    # or rkf45

One of my colleagues wants the solution in array form for using it in a spreadsheet (namely Excel). 
Here is an example of what I do :
 
data := plottools:-getdata( plots:-odeplot(sol, […..], 0..Tend, refine = Q) ):  # Q rational
result := data[3]:
ExcelTools:-Export (result, …)

To understand the following, you need to know that the time step varies by several decades (at least 3 or 4). and that  numfun is typically in the order of 10^5
 
When I ask Maple to construct  data , Maple seems to sample the solution solaccording to the local time step dsolve has selected (and probably some other parameters ?)
Because this time step varies in very large proportions, the result is sometimes a concentration of points in regions where the solution is rapidly changing (which is desirable) … with some lacunarity in slow varying regions.

To obviate this, sometimes  poor appearance, I used to force Maple to compute the solution by regularly sampling the range ]0, Tend[  and combining this array with the original one (result).
But this not satisfactory for I do not avoid lacunarity region (unless I proceed in some ad hoc way)

Here is my question :
Could you give me some elements about  the way odeplot adapts its sampling strategy according to the local time step, the budget N (the Q value I guess) and maybe numfun ?

Thank you in advance

Dear readers,

For a question for my students I want them to calculate tge resulting vector from two vectors. The student had to answer by giving the length and angle of the resulting vector.

For the question the vector angle is always larger as 180 derges, the student should for example give a result of 270 degrees.

Currently I'm using the following code:

$F1=100;#range(200,500,20);
$F2=100;#range(100,200,10);
$A1=45;#range(10,80,5);
$A2=45;#range(10,80,5);
$A1r=180+$A1;
$A2r=360-$A2;
$F1x=maple("cos(($A1r)*Pi/180)*$F1");
$F1y=maple("sin(($A1r)*Pi/180)*$F1");
$F2x=maple("cos(($A2r)*Pi/180)*$F2");
$F2y=maple("sin(($A2r)*Pi/180)*$F2");
$V1=maple("Vector(2,[($F1x),($F1y)])");
$V2=maple("Vector(2,[($F2x),($F2y)])");
$V3=maple("($V1)+($V2)");
$F3=maple("LinearAlgebra[Norm]($V3)");
$V0x=maple("Vector(2,[1,0])");
$A3=maple("LinearAlgebra[VectorAngle](($V0x),($V3))");
$A4=maple("evalf((($A3)*180/(Pi)))");

As you can see maple will always give an angle smaller than 180 degrees since the angle between two vectors is always 180 degrees or smaller.

Can anyone tell me how I should code this problem such that the rest for A4 will be 270 degrees rather than 90 degrees, as is given from the current way of coding.

Thank you in advance.

I have excuted a loop for i from.....by...while.....do l2:=NLPSolve(.......) with variables, t1,th,tl, etc. I need get the numerical result of theses variables and assign them to t1,th, etc. After execute a function with them. I have tried with op, map and assign, but the program don't understand the numerical value of variables. Why?. How can i assign theses numerical vaules?. Thanks! 

hi

please help to me for solve this equation via pdsolve?

thanks

dsove2.mw

Download dsove2.mw