Hello,

I have just updated maplesim to the last version (maplesim2015).

On the multibody examples of the maplesim2015 library, I didn't have any problems.

However, when i try to launch a simulation on a model i have made with a previous version (which worked before I use maplesim2015), i meet this problem :

May you help me to make the troubleshooting ? For the moment, I didn't manage to locate the error.

Do you have some ideas about this mistake ?

Thanks a lot for your help.

Hello, dear experts.
I have a question...
I solve the system of differential equations,where one of the initial conditions need to be chosen so thatcondition is metat the end of integration.
The task is not difficult, but I'm having trouble with the syntax.

1.I can't "pull"the desired function from the solution and find its value at a certain point.
I try to do so:
r_ravn:=s->subs(F,r(s));
evalf(r_ravn(s_end));
evalf(r_ravn(0));
but there is no result
2.In this case,instead of"for"it is better to use a while loop, but again the problem arises 1.
Tell me, please,how to implemen my program.

restart:
R:=0.3:
theta_min:=Pi/6:
theta_max:=Pi/2:
betta_max:=evalf(Pi/180*80);
p:=2*10^5:

theta0:=s->Pi/3/s_end*s+Pi/6:
r0:=s->R*sin(theta0(s)):
s_end:=evalf(R*(theta_max-theta_min)):

sol1:=solve({sin(betta_max)=c/r0(0)},{c});
const1:=0.1477211630;

betta0:=s->arcsin(const1/r0(s)):
betta:=s->arcsin(r(s)/r0(s)*sin(betta0(s))):
A:=s->cos(betta(s))/cos(betta0(s)):
T1:=s->rT1(s)/r(s):
T2:=s->T1(s)*tan(betta(s))^2:

step:=0.001:
delta:=0.001:
for i from 1 to 3000 do
r_min:=0.3-step:
rT1_n:=p*Pi*r_min^2/2/Pi/sin(theta_min):

sys := diff(rT1(s), s)-A(s)*T2(s)*cos(theta(s)),diff(theta(s), s)-A(s)/T1(s)*(p-T2(s)*sin(theta(s)/r(s))),diff(r(s),s)-A(s)*cos(theta(s)),diff(z(s),s)-A(s)*sin(theta(s));
fcns := {rT1(s),theta(s),r(s), z(s)};
F := dsolve({sys,rT1(0)=rT1_n, theta(0)=theta_min,r(0) = r_min, z(0) = 0}, fcns, numeric,output=listprocedure):
r_ravn:=s->subs(F,r(s)):
if abs(evalf(r_ravn(s_end))-R)=delta then break:
print(r_min):
end if:
end do:

r_ravn:=s->subs(F,r(s));
evalf(r_ravn(s_end));
evalf(r_ravn(0));
plot([r_ravn(s),r(s)],s=0..s_end);

Hello,

i did see that u can calculate minimial polynomials for for example \sqrt(2) or smth.

Suppose now u have a ground field K and an extension L=K(p,q) where p,q are some given rational functions in the indeterminates x,y, now i would like to calculate the minimal polynomial for lets say x+y or x over L which then obviously splits over the field K(x,y).

Thx in advance

(in dsolve/numeric/bvp) initial Newton iteration is not converging.

Dear Maple users

I am unsure how to handle events and their probabilities in Maple. Let's say I know that an event A has the probability say 0.3 and another event B has probability 0.8. I would like to make the following assignments:

P(A):=0.3:

P(B):=0.8

and maybe defining the conditional probability:

P(A|B):=0.55

but I am not allowed to do so in Maple because if will regarded as a function definition. My purpose is to make simple calculations with those probabilities for example:

P(C):=P(A)*P(B)  etc.

My problem is therefore more of a notational problem than a mathematical one. I hope someone can advice me on a proper setup. I am using 2D math notation, by the way. I could of course name the variables containing the probability using simple names like X1, X2, etc., but then I need constantly to remember what they really mean. The above assignments would be much better, because they are easier to handle mentally.

Regards,Erik

Trying a few integrals in Maple -- doesn't seem to handle them very well. Any workarounds please?

f1(p,b):= 1/(p^2 + b^2)^2 ;

f2(p,b):= exp(-p/b)^2;

T1pbm := Int(q*f1(q, b)*ln((p+q)^2+m^2), q = 0 .. infinity);

T2pbm := Int(q*f1(q, b)*ln((p-q)^2+m^2), q = 0 .. infinity);

with(IntegrationTools):

PT1 := evalf(Parts(T1pbm, q*f1(q, b), ln((p+q)^2+m^2)));

PT2 := evalf(Parts(T2pbm, q*f1(q, b), ln((p-q)^2+m^2)));

Ev := evalf(-pi*c*Int*(p*f1(p, b)*(PT1-PT2), p = 0 .. infinity))

The following toy procedure does not work (I give a value to a symbol). How to make it work ? Thanks.

Hi .please help me for solve this nonlinear equations , that attch below

thanks a lots.....

dsys3 := {8*(diff(f2(x), x, x, x, x))+9*(diff(f2(x), x, x))+10*f2(x)+11*(diff(f1(x), x, x, x))+12*(diff(f1(x), x))+13*(diff(f3(x), x, x))+14*f3(x)+f3(x)*f3(x)+(diff(f3(x), x))*(diff(f3(x), x))+(diff(f3(x), x, x))*f3(x) = 0, 16*(diff(f3(x), x, x, x, x))+18*(diff(f3(x), x, x))+19*(diff(f3(x), x, x))+22*(diff(f1(x), x))+23*(diff(f1(x), x))+24*(diff(f2(x), x, x))+25*f2(x)+26*f2(x)+27*f3(x)+29*f3(x) = 0, 2*(diff(f1(x), x, x))+3*(diff(f2(x), x, x, x))+4*(diff(f2(x), x))+6*(diff(f3(x), x))+7*f1(x)+(diff(f3(x), x, x))*(diff(f3(x), x))+(diff(f3(x), x))*f3(x)+(diff(f3(x), x))*f3(x) = 0, f1(0) = 0, f1(1) = 0, f2(0) = 0, f2(1) = 0, f3(0) = 0, f3(1) = 0, ((D@@1)(f2))(0) = 0, ((D@@1)(f2))(1) = 0, ((D@@1)(f3))(0) = 0, ((D@@1)(f3))(1) = 0}; dsol5 := dsolve(dsys3, 'maxmesh' = 500, abserr = .1, numeric, range = 0 .. 1, output = listprocedure)12.mw

I have calculated coefficients in maple using a "for...end do" command. For example,

for n from 0 to 1 do A[n] = int(((2*n+1)*(1/2))*simplify(LegendreP(n, cos(theta)))*sin(theta), theta = 0 .. (1/2)*Pi) end do;


A[0] = 1/2

A[1] = 3/4

Here, I can calculate as many coefficients as I want. But, how do I use these coefficients in the following line? For example, I need to calculate a summation. But for each term in the summation, I want to input the coefficients above to the corresponding term in the sum. So. the following summation

 A[0]+A[1]*r*cos(theta)+...

will automaticlly attach the numerical values of the coefficients calculated above to the corresponding term in the sum.

I hope this makes sense.

I know the Wronskian command. I want to use this command for detecting linearly dependence or independence of some polynomials. I know that the polynomials  are  linearly independent if the Wronskian is not zero.  Conversely, if the Wronskian vanishes  then the polynomials are linearly dependent. Now I want to know that how can I find the coefficient vector if the polynomials are dependent by Wronskian command?

For example if [f1,f2,f3] be a list of polynomials s.t. a1f1+a2f2+a3f3=0. How can I find a1, a2, a3? 

I would like to overwrite a plot that's updated within a loop over time. 

I used animate already, but the problem is that it's  only updated at specific points in time (not regularly distributed) and with animate I can only use frames that are equally divided over the wholre range. To update each time step costs unneeded memory and time. 

I hope that there exists a better solution.

thanks for your help.

hi,

how can I convert the decimal representation of the symbolic expressions: I dont want the result in terms of symbols like e^5 or ln(3) 

thanks

Hi,

I have a system of nonlinear equations in conjuction with boundary conditions, as below:

(all coefficients are constant.)

dsys3 := {a2*(diff(f1(x), x, x))+a3*(diff(f2(x), x, x, x))+a4*(diff(f2(x), x))+a6*(diff(f3(x), x))+a7*f1(x)+a1N*(diff(f3(x), x, x))*(diff(f3(x), x))+a2N*(diff(f3(x), x))*f3(x)+a3N*(diff(f3(x), x))*f3(x) = 0, a8*(diff(f2(x), x, x, x, x))+a9*(diff(f2(x), x, x))+a10*f2(x)+a11*(diff(f1(x), x, x, x))+a12*(diff(f1(x), x))+a13*(diff(f3(x), x, x))+a14*f3(x)+a4N*(f3(x)*f3(x))+a5N*((diff(f3(x), x))*(diff(f3(x), x)))+a6N*(diff(f3(x), x, x))*f3(x) = 0, (diff(f3(x), x, x, x, x))*a16+(diff(f3(x), x, x))*a18+(diff(f3(x), x, x))*a19+(diff(f1(x), x))*a22+(diff(f1(x), x))*a23+(diff(f2(x), x, x))*a24+f2(x)*a25+f2(x)*a26+f3(x)*a27+f3(x)*a29 = 0, f1(0) = 0, f1(1) = 0, f2(0) = 0, f2(1) = 0, f3(0) = 0, f3(1) = 0, ((D@@1)(f2))(0) = 0, ((D@@1)(f2))(1) = 0, ((D@@1)(f3))(0) = 0, ((D@@1)(f3))(1) = 0}:
dsol5 := dsolve(dsys3, 'maxmesh' = 500, abserr = .1, numeric, range = 0 .. 1, output = listprocedure)

but i encounter an error as:

Error, (in dsolve/numeric/bvp/convertsys) unable to convert to an explicit first-order system

what is your suggestion to solve this nonlinear equations?

Thank you.

Hi everyone,

I have a great problem with the evaluation of following definite integral

> restart;

> int((t-x)^2)/(1+2t+(1/2)t^2-ln(t^2+2t+2)t-ln(t^2+2t+2)+arctan(1+t)t^2+2arctan(1+t)t+ln(2)t+ln(2)-(pi/4)t^2-(pi/2)t)^2,t=0..x)

I have tried different classical commands but Maple doesn't give an answer. Probably, it's just a silly fault.

Does anyone knows how to solve it?

Thanks.