I define unit vectors as

Then I manually take the dot product as

and get

But when I do this

I get

How can I make Maple give me the first result using the sum command?

------------------------------------------------------------------------------------------------------------------------------

restart:

Digits :=30: m := 4: g :=0.3: nu := 0.4: a := 1:k:=0.2:

W:=cos(n*2*evalf(Pi)*( r-k*a)/((1-k)*a)):

ODE:=((2*(diff(W, r, r, r, r))+2*(diff(W, r, r, r))/r-4*(diff(W, r, r))/r^2+4*(diff(W, r))/r^3-(2*(1-nu))*(diff(W, r, r, r))/r+(4*(1-nu))*(diff(W, r, r))/r^2-(4*(1-nu))*(diff(W, r))/r^3)*r*(1+g*r/a)^3+(2*(2*(diff(W, r, r, r))+2*(diff(W, r, r))/r-2*(diff(W, r))/r^2-(2*(1-nu))*(diff(W, r, r))/r+(2*(1-nu))*(diff(W, r))/r^2))*(1+g*r/a)^3+(6*(2*(diff(W, r, r, r))+2*(diff(W, r, r))/r-2*(diff(W, r))/r^2-(2*(1-nu))*(diff(W, r, r))/r+(2*(1-nu))*(diff(W, r))/r^2))*r*(1+g*r/a)^2*g/a+(6*(2*(diff(W, r, r))+2*(diff(W, r))/r-(2*(1-nu))*(diff(W, r))/r))*(1+g*r/a)^2*g/a+(6*(2*(diff(W, r, r))+2*(diff(W, r))/r-(2*(1-nu))*(diff(W, r))/r))*r*(1+g*r/a)*g^2/a^2-((2*(diff(W, r, r, r)+(diff(W, r, r))/r-(diff(W, r))/r^2))/r-(2*(diff(W, r, r)+(diff(W, r))/r))/r^2-(2*(1-nu))*(diff(W, r, r, r))/r+(2*(1-nu))*(diff(W, r, r))/r^2)*r*(1+g*r/a)^3-((2*(diff(W, r, r)+(diff(W, r))/r))/r-(2*(1-nu))*(diff(W, r, r))/r)*(1+g*r/a)^3-(3*((2*(diff(W, r, r)+(diff(W, r))/r))/r-(2*(1-nu))*(diff(W, r, r))/r))*r*(1+g*r/a)^2*g/a)/(2*(diff(W, r, r))*r+2*(diff(W, r))) :

for i from 1 to m do  for j from 1 to m do
C[i,j]:=int(subs(n=i,ODE)*subs(n=j,W),r=k*a..a)
end do:end do:

Why does the collect command work for some expressions and not for others. Here is a screen shot

I assume the collect command is supposed to rewrite the expression in terms of the variable descending order.

p := expand((a^2+2*x)*(a^2+2*x));
                        4      2        2   2
                       a  + 4 a  x + 4 x

collect(p, x);
                        4      2        2   2
                       a  + 4 a  x + 4 x

Does not work.

But if you look at the screenshot , it works for other expressions.

I found an error in a file I posted that I would like to correct. Can I modify the existing post? Delete it and make an new one?

I am trying to solve and plot a diff. eq. with two initial condtions and keep getting the same error.

F1 := diff(x(t), `$`(t, 2))+omega^2*sin(x(t)) = 0;

g := 9.8; L := 1; omega := g/L;

sol := dsolve({F1, D(x)*0 = 0, x(0) = (1/2)*pi}, x(t), numeric);
Error, (in dsolve/numeric/process_input) invalid specification of initial conditions, got 0 = 0

 any help or suggestions would be appreciated

I have some X-Y data, and I would like to calculate a definate integral of the data. In this case x_data and y_data are vectors.

I tried this method.

y:=x->ArrayInterpolation(x_data,y_data,x)

But when I try to calculate an integral like this, I get an error.

int(y, x0..x1)

Error, (in int) operator y cannot be evaluated at one variable.

What is this error trying to tell me? I have tested by function y for values x1 and x2. My data is smooth and includes x1 and x2. I have no reason to believe that the function cannot be evaluated for any value of x. 

Is there another (better) way to do what I want? This is a part of a large worksheet that reads data from an excel file, and I don't know how to reduce the worksheet for only this problem.

Thanks.

A procedure can be made available in many worksheets by copying its original commands to each such worksheet. Is there a better way to include and invoke such a procedure in multiple worksheets?

with(Physics):
L := diff(q2(t), t)
diff(L, q2(t))

it return 0, is it correct?

Warning, unable to evaluate the function to numeric values in the region; see the plotting command's help page to ensure the calling sequence is correct

For the life of me I can not get maple to plot this equation.  I have poured over various resources and it simply isn't working.  I have gone so far as to use SIMPLIFY and even  Re(circuitSix) and Im(circuitSix) yet still get only errors.  Any insight would be appreciated.

I want to make a nested loop and store the data(with complex numbers) in matrix in order to make 3D plot.

The function hypergeom([2/3,2/3,2/3],[-1/3,4/3],z) has radius of convergence 1 and real coefficients.

But Maple tells me evalf(hypergeom([2/3, 2/3, 2/3], [-1/3, 4/3], 99/100),50);

is -138.999 + 0.0012 I
 

It should be more like −138.9962313171333091754979138344422738025

(Maple 18, version 991181)

---

G A Edgar

Hi everyone,

I would like to create an eBook with the pakage "eBookTools", but I have got several errors if in my mw document there is a table. The same error came out if I try to compile a book with the sample documents ("GettingStartedWithMaple.mw"). Anyone knows a solution?

Thank you for your time

Giorgio

a1 := Matrix(3, [1, 2, 3, 7, 8, 9, 13, 14, 15]);
a2 := Matrix(3, 2, [5, 6, 11, 12, 17, 18]);
a3 := Matrix(2, [19, 20, 25, 26]);
a2 := Matrix(3, 2, [5, 6, 11, 12, 17, 18]);



i want to combine above matrices in big matrix like

A := Matrix(2, 2, [a1, a2, a3, a4]);

best regards

I am using Maple-9 to simplify the expression and the expression is not having numerical coefficients. Example expression is given below.

a2:=(18*d^2*R^2*r-4*d1^3*r+5*R^6-z1*r^3*p-14*r1^3*r*rc+k1*d^2*R^2*r);

The question here is: I want to collect all "positive terms" and "negative terms" and assign to new variable.

Please suggest steps for the above problem

Thank you in advance.