Assume that I have r:= -6x+3y+23x²-4xyz+7z² . By using coeffs(r,x,'k') I can find the coefficients of 1, x, and x². 

What should I write to get the conditions that make the coefficient of x zero? How can I just pick the coefficient of x, and solve it. 

I have several coefficients but the answer of this question will help me. 

Hello,

I use a map() command to get the values of function for each element of vector. Here is an example of a simple task:

restart:

A:=[1,2,8];

f1:=x->2*x;
f1_table_A:=Vector([map(f1,A)]);

I would like to do the same with piecewise function but it doesn't work. Here is an example:

restart:
with(plots):
f:=2*x:
g:=x^2:

h:=x->piecewise( 0<=x and x<= 5, f, 5<x and x <= 10, g ) ;
A:=[1,2,8]:
h_table_A:=map(h,A):

Is it possible to work with piecewise function? Maybe someone has an idea how to do it in different way?

Kind regards,

Iza

Hi all,

I need to solve det[M]=0 for omega.

M is:

M := Matrix(8, 8, {(1, 1) = BesselJ(n, tp*a), (1, 2) = 0, (1, 3) = 0, (1, 4) = 0, (1, 5) = -BesselJ(n, tg*a), (1, 6) = -BesselY(n, tg*a), (1, 7) = 0, (1, 8) = 0, (2, 1) = k*n*BesselJ(n, tp*a)/(tp^2*a), (2, 2) = I*k*n*mu0*omega*(diff(BesselJ(n, tp*a), a))/(tp^2*a), (2, 3) = 0, (2, 4) = 0, (2, 5) = -k*n*BesselJ(n, tg*a)/(tg^2*a), (2, 6) = -k*n*BesselY(n, tg*a)/(tg^2*a), (2, 7) = -I*`&mu;g`*omega*(diff(BesselJ(n, tg*a), a))/tg^2, (2, 8) = -I*`&mu;g`*omega*(diff(BesselY(n, tg*a), a))/tg^2, (3, 1) = 0, (3, 2) = BesselJ(n, tp*a), (3, 3) = 0, (3, 4) = 0, (3, 5) = 0, (3, 6) = 0, (3, 7) = -BesselJ(n, tg*a), (3, 8) = -BesselY(n, tg*a), (4, 1) = -I*omega*`&varepsilon;p`*(diff(BesselJ(n, tp*a), a))/tp^2, (4, 2) = k*n*BesselJ(n, tp*a)/(tp^2*a), (4, 3) = 0, (4, 4) = 0, (4, 5) = I*`&varepsilon;g`*omega*(diff(BesselJ(n, tg*a), a))/tg^2, (4, 6) = I*`&varepsilon;g`*omega*(diff(BesselY(n, tg*a), a))/tg^2, (4, 7) = -k*n*BesselJ(n, tg*a)/(tg^2*a), (4, 8) = -k*n*BesselY(n, tg*a)/(tg^2*a), (5, 1) = 0, (5, 2) = 0, (5, 3) = k*n*BesselY(n, t0*b)/(t0^2*b), (5, 4) = I*mu0*omega*(diff(BesselY(n, t0*b), b))/t0^2, (5, 5) = -k*n*BesselJ(n, tg*b)/(tg^2*b), (5, 6) = -k*n*BesselY(n, tg*b)/(tg^2*b), (5, 7) = -I*`&mu;g`*omega*(diff(BesselJ(n, tg*b), b))/tg^2, (5, 8) = -I*`&mu;g`*omega*(diff(BesselY(n, tg*b), b))/tg^2, (6, 1) = 0, (6, 2) = 0, (6, 3) = BesselY(n, t0*b), (6, 4) = 0, (6, 5) = -BesselJ(n, tg*b), (6, 6) = -BesselY(n, tg*b), (6, 7) = 0, (6, 8) = 0, (7, 1) = 0, (7, 2) = 0, (7, 3) = 0, (7, 4) = BesselY(n, t0*b), (7, 5) = 0, (7, 6) = 0, (7, 7) = -BesselJ(n, tg*b), (7, 8) = -BesselY(n, tg*b), (8, 1) = 0, (8, 2) = 0, (8, 3) = -I*epsilon0*omega*(diff(BesselY(n, t0*b), b))/t0^2, (8, 4) = -k*n*BesselY(n, t0*b)/(t0^2*b), (8, 5) = I*`&varepsilon;g`*omega*(diff(BesselJ(n, tg*b), b))/tg^2, (8, 6) = I*`&varepsilon;g`*omega*(diff(BesselY(n, tg*b), b))/tg^2, (8, 7) = -k*n*BesselJ(n, tg*b)/(tg^2*b), (8, 8) = -k*n*BesselY(n, tg*b)/(tg^2*b)});

and n=0,1,2.

Except of omega and k ,other parameters is canstant.

After using
with(LinearAlgebra):
detM := Determinant(M):

I used solve(detM=0,omega) and fsolve() but it dosnt work. how can i solve it?

Thanks alot.

can anyone please help me to find roots of (2*cos(0.5*x)*sin(0.5*x)*cos(3.775*x)+2.2075*((cos(0.5*x))^2)*sin(3.775*x)-0.453*((sin(0.5*x))^2)*sin(3.775*x)=0 ?

i type on maple like this:

solve(2*cos(0.5*x)*sin(0.5*x)*cos(3.775*x)+2.2075*((cos(0.5*x))^2)*sin(3.775*x)-0.453*((sin(0.5*x))^2)*sin(3.775*x)=0);

but it said the solutions may have been lost

thanks before

Working on a code to create random lines. Here is the code: 

M:=1; N:=1500; R3:=rand(1..3): # M=lines, N=steps

for i from 1 to M do
X[i,0]:=0;
Y[i,0]:=0;
   for j from 0 to N do
   if j=1 then X[i,1]:=1; Y[i,1]:=0;
    elif j>1 then
      r:=R3();
        if r=1 then X[i,j]:=2*X[i,j-1]-X[i,j-2]; Y[i,j]:=2*Y[i,j-1]-Y[i,j-2]
        elif r=2 then X[i,j]:=X[i,j-1]+Y[i,j-1]-Y[i,j-2]; Y[i,j]:=Y[i,j-1]-X[i,j-1]+X[i,j-2];
        elif r=3 then X[i,j]:=X[i,j-1]-Y[i,j-1]+Y[i,j-2]; Y[i,j]:=Y[i,j-1]+X[i,j-1]-X[i,j-2];
      end if;
    end if;
   R[i,j]:=[X[i,j],Y[i,j]];
   K[i,j]:=[X[i,j],Y[i,j]];
  end do:
end do:

Now the code works fine. But I don't want the lines to cross its own path. I want it to stop if R[i,j]=R[i,k] for any 0<k<i-2 for j=0..N. What I have so far is:

for i from 1 to M do
  for j from 1 to 40 do
    R[i,j];
    for k from 1 to j-2 do
     if R[i,j]=K[i,k] then x:=j; print(b[i]=j); break; end if;
     L[i,j]:=R[i,j];
     end do;
   end do;
end do;

Now it works aswell, but it doesn't stop when it hits the crossing point. I want it to stop so i get one b[i]=j per M. So I need it to break two for loops so that it goes through i M times and stops everytime it reaches a crossing point

Hello,

I am trying to differentiate a matrix containing four variables, alpha, alphaB (representing alpha bar), beta, and betaB (for beta bar). They are are variables with respect to t. I then need to let t=0 and then simplify the result with some initial conitions i have. Could you tell me any useful maple functions which i can use to do this? If you need anymore information let me know and thank you for helping me.

Robbie

we have a curve (x^2+y^2)^2=x^2-y^2

parametric representation of the curve is given by

x(t)=cos(t)/1+sin^2(t)

y(t)=sin(t)cos(t)/1+sin^2(t)

and we are asked to plot the curve using a parametric plot for -Pi<t<Pi

Dear

Hope everything going fine with you. I have question

f := x^11+2*x^9+2*x^8+x^6+x^5+2*x^3+2*x^2+1

g := 2*x^10+x^7+2*x^4+x

if we take gcd of infinite field its answer is x^6+1 

and the GCD(3)[x]=Z_3[x] is given by x^9+2x^6+x^3+2

How we find GCD(3)[x] in maple. 

With my best regards and sincerely.

Hi,

I'm trying to create a code that allows me to model a random walk for 50 people. I'm using r[i]= {X[i],Y[i]} where i is the number of steps and r[i] the position in the i-th term.

I have created three possibilities:
2r[i]-r[i-1] - go stright forward

{x[i]+y[i]-y[i-1],y[i]-x[i]+x[i-1]} - turn right

{x[i]-y[i]+y[i-1],y[i]+x[i]-x[i-1]} - turn left

The first step I want them to make is to point (1,0) and from there I want them to take 1500 random steps.

M:=50; N:=1500; R3:=rand(1..3):

for i from 1 to M do
X[i,0]:=0;
Y[i,0]:=0;
R[i,0]:=[X[i,0],Y[i,0]];
for j from 1 to N do
R[i,j]:=[X[i,j],Y[i,j]];
if j=1 then X[i,1]:=1; Y[i,1]:=0;
elif j>1 then
r:=R3();
if r=1 then R[i,j]:=2*R[i,j]-[R[i,j-1];
elif r=2 then R[i,j]:=[X[i,j-1]+Y[i,j-1]-Y[i,j-2],Y[i,j-1]-X[i,j-1]+X[i,j-2]];
elif r=3 then R[i,j]:=[X[i,j-1]-Y[i,j-1]+Y[i,j-2],Y[i,j-1]+X[i,j-1]-X[i,j-2]];
end if;
end if;
end do:
end do:

The first and second step works, but from there it seems Maple is having trouble getting the correct digigts, because the formulas coming out are correct.

I have tried putting in different types of X, Y and R reads, but have gotten stuck. If someone could help me spot what this code is missing I would be very gratefull. I think Maple is just missing a way of reading X and Y but i might be wrong.

when the variable is in limits of integration?

hw2_example.mw

there exist an error : 

Error, (in int) unable to compute a numeric answer for symbolic limits, q = -3.141592654+arccos(11./(1.+.1000000000*t)) .. 3.141592654-1.*arccos(11./(1.+.1000000000*t))

How to make this code work?

hello

how to solve lp  on maple when consrtaints are in interval 

eg

0<x<1

 i try to find this on maple,but i could not found my desired ans.

i got an assignment in which 15 constraints are given and all are in interval.

anyone know the ans then plz help me

How many numbers exist which are: less than 1000, multiple of 18 and also multiple of 10? Use Maple to find the answer 

Hello everyone! My English is not very good. 

I have writtien Lucas sequence program:

F := proc (n::nonnegint)

option remember;

if n < 2 then n else F(n-1)+F(n-2) 

end if;

end proc;

L := proc (n::nonnegint)

if n = 0 then return 2 end if;

if n = 1 then return 1 end if;

if n <> 0 and n <> 1 then return

L(n-1)+L(n-2) end if; end proc;

S:=proc(n::nonnegint)

 local i;  

for i from 1 by 1 to n do   S(i)=L(i)^(2)-5*F(i)^(2);

 print("%a",S(i));  end proc: 

And Maple notice :error

I don't know call procedure inside another procedure. 
Thank you so much

Regards

sunflower

Hello everyone!

I'd like to as a question that might be very simple, but the thing is that I am completely new to Maple, and I have some homework I need to solve all of a sudden... I tried watching some tutorials and did a lot of search, but I just can't make this one work.
Briefly - my task is to derive the vibrational modal shapes of an annular disk (a circular disk with the center "missing"). So far what I know for sure is, that the radial term of the vibrational deflection is given as a linear combination of 4 types of bessel functions (J_n, Y_n, I_n and K_n) - bessel functions of the 1st and second kind, and modified bessel functions of the 1st and second kind. Something like this:

R_mn(r) = A*J_n(kr) + B*Y_n(kr) + C*I_n(kr) + D*K_n(kr).

Now, I need to find the values for k (the wavenumber), and the coeffitients B, C and D. I don't need coeffitient A, because I'll jus fix that to be 1. To do this, I have the following 4 boundary conditions:

1) R_mn(b) = J_n(kb) + B*Y_n(kb) + C*I_n(kb) + D*K_n(kb) = 0

2) R'_mn(b) = k(J_n'(kb) + B*Y_n'(kb) + C*I_n'(kb) + D*K_n'(kb)) = 0

3) R''_mn(a) = k²(J_n''(ka) + B*Y_n''(ka) + C*I_n''(ka) + D*K_n''(ka)) = 0

4) R'''_mn(a) = k³(J_n'''(ka) + B*Y_n'''(ka) + C*I_n'''(ka) + D*K_n'''(ka)) = 0

So, four equations in four unknowns (k, B, C and D) - and I can't get it to work.

I did the following, and it gives me some totally wrong values (complex wavenumbers and such). Again, I am completely new to Maple, so I might have done something completely silly without even noticing...

b := 0.17e-1;
a := 0.8e-1;
n := 1;

R(r) := BesselJ(n,k r) + B BesselY(n, k r) + C BesselI(n, k r)  + D BesselK(n, k r) ;

eq1 := R(b) = 0;
eq2 := eval(diff(R(x), x), x = b) = 0;
eq3 := eval(diff(R(x), x, x), x = a) = 0;
eq4 := eval(diff(R(x), x, x, x), x = a) = 0;

solve([eq1, eq2, eq3, eq4], [k, B, C, D])

What is it, that I am not doing right?

Thank you very very much for the help in advance!
Andras

I have in mind

.

My unsuccessful trials are

evalf(Int(cos(log(x)/x)/x, x = 0 .. 1, method = _d01akc));

Error, (in evalf/int) NE_QUAD_MAX_SUBDIV:
  The maximum number of subdivisions has
  been reached: max_num_subint = 500

and

evalf(Int(cos(log(x)/x)/x, x = 0 .. 1, method = _d01akc, methodoptions = [maxintervals = 2000]));

Error, (in evalf/int) NE_QUAD_MAX_SUBDIV:
  The maximum number of subdivisions has
  been reached: max_num_subint = 2000

and

evalf(Int(cos(log(x)/x)/x, x = 0 .. 1, method = _d01ajc));

Error, (in evalf/int) NE_QUAD_NO_CONV:
  The integral is probably divergent or slowly convergent.

Mathematica cracks it without any options, producing 0.323367.