Dear Forum,

I have a rational transfer function, like

Y(s)/X(s)=G(s)=(s^2+s+1)/(s^3-3*s^2+5)

With the DynamicSystems package, Maple can compute a state space representation, but I want a single DEQ in y(t) of 3rd order. What is the best way to let Maple compute this?

I wrote the following MAPLE code

restart; N := 2

alias(epsilon = e, eta = t)

eq1 := 5*(diff(F(t), `$`(t, 3)))+(1+3*e)*F(t)*(diff(F(t), `$`(t, 2)))-(2+e)*(diff(F(t), t))^2 = 0

F := proc (t) options operator, arrow; sum('F[i](t)*e^i', 'i' = 0 .. N) end proc

deqn := simplify(collect(eq1, e), {e^(N+1) = 0})

MAPLE says

Error, (in sum) too many levels of recursion

How do I get this error corrected?

I am having trouble identifying all the possible roots existing in the range specified.

In the file attached i have a non-linear set of equations that are solved for "w" value specified...but fsolve provides solutions only at certain values of "w" , does it mean there is no solution for other data points ?...or is there a way to find out all possible solutions for each value of "w"

Question_primes.mw

I have an electric field as a function of time and space.It is a uniform plane wave.

E(r,t)= 3*cos(w*t-k*z+Pi/4)x+ 2*sin(w*t-k*z-Pi/3)y

where r is the space vector r=xx+yy+zz; 

x   y and z are unit vectors.

w and k are constants.

How can I plot it?

Please write a code for me about following problem.

Let A(0,1,2) be a point and two lines

d1: x/2 = (y-1)/1 = (z+1)/(-1)

d2: x = 1 + t, y = -1 + 2t, 2 + t.

Find the coordinates of the 

Let a list of n positive integers be given, e. g. [2,1,4].
Let us consider all sums of  all its members signed by +-, e. g
-2-1-4=-7, -2+1-4=-5, -2-1+4=1, ... .
How to find the sum having the minimum  absolute value with Maple?

Problem: Write the equation of the straight line (d) through the point A(1,-2,3), cut the straight line 

Delta: x = 3*t+1, y = t, z = t-1 and parallel to the plane (P): x + 2*y + 3*z + 4 = 0.

We know that, if the straight line (d) through the point A and parallel to the plane (P), then (d) lies on a plane (Q), which (Q) through the point A and parallel to the plane (P).

Here is a simple example from the Maple Help (nersion 9.03):
###
i := 5; cat( "The value of i is ", i, "." );
###
which yields
  "The value of i is 5."

I would like to use the same syntax to generate a string to be printed at the beginning of a data file (so that I can remember what are the figures in the files); for instance I want to specify that this set has been generated choosing the value of a parameter alpha to be 0.618. So I write

Write the equation of a pane (P) which passes through the point E(2,1,0) and F(1,2,1) such that distance from the point A(1,-2,-1) to the plane (P) twice distance from the point B(2,4,3) to the plane (P).

My main idea is based on, if the line (d) passes through...

is(sum( (1+i)^(k-1), k = 1 .. 8) = sum( (1+i)^(k-1), k = 8 .. 1))
                                                       false

Is that a bug in sum that got fixed in a newer Maple or maybe I missed something?...

Problems concerning integration have been discussed on  maple primes  before with piecewise continuous antiderivatives explaining  difficulties. Here an example is given using Maple 15 where a continuous antiderivative is returned but definite integration fails to give the correct answer.

Integration_anomal.mw

Dear All,

I am trying to solve the following equation in Maple but could not find the actual result:

P:=1/2 * Real (E x H*)

How to find the real value of (E x H) with H*= H conjugate.   And also which command to solve for the value P.

Your help will really be appreciated

Thanks in advance

A.Q

Soton

HI,

I've got a MapleCode with exports the data in the end into an ".txt"-File. Now it's necessary to create an"Tab" instead of the semicolon, which is produced now between A and B.

Now: "A;B"

Should be: "A    B" (Tab between).

> fd := fopen("C:/ZZZ_TEST4.txt", WRITE);
                      ...

I wrote a program in order to find coordinates orthocenter of the triangle. Please comment for me. This is my code:

restart;

with(geom3d);

point(A,1,-3,0);

point(B,-2,1,1);

point(C,3,1,2);

line(AB,[A,B],t);

line(BC,[B,C],t);

ab:=ParallelVector(AB); 

bc:=ParallelVector(BC);

eq1:=Equation(plane(P,[C,ab],[x,y,z]));

eq2:=Equation(plane(Q,[A,bc],[x,y,z]));

eq3:=Equation(plane(ABC,[A,B,C],[x,y,z]));

How can I replace/substitute a combination of variables with a new variable?

For example, if ...

h:=(1+i)^2+(1+i)^3*A+(1+i)^4*B

I want to assign the value g:=1+i

so that h returns g^2+g^3*A+g^4*B

Do I have to change the 1+i to a name? or can it be done as it is?