Hi! Any help would be greatly appreciated :)

I have two matrices S and R, where 

S := Matrix( [ [a_1, a_2, a_3, a_4], [b_1, b_2, b_3, b_4], [c_1, c_2, c_3, c_4], [d_1, d_2, d_3, d_4] ] );

such that 

a_1*d_1 = b_1*c_1
a_2*d_2 = b_2*c_2
a_3*d_3 = b_3*c_3
a_4*d_4 = b_4*c_4;

and 

R := Matrix( [ [s_1, t_1, r_1, l_1], [s_2, t_2, r_2, l_2], [s_3, t_3, r_3, l_3], [s_4, t_4, r_4, l_4] ] );

such that 

I am trying to get Maple to calculate for me.. Let X and Y have a trinomial distribution with parameters n=3, p1=1/6 and p2=1/2. I am supposed to find E(X), E(Y), Var(X), Var(Y) and Cov (X,Y). Thank you to anyone who can assist with this. And if  you can help me understand the concept behind it.. Im having some troubles with bivariate distributions in my Stats course :( Thanks!

In Maple 15.01, the commands

   f := x -> sin(2 x)
   h := n -> (1/Pi) int(f(x) sin(n x), x = -Pi .. Pi)
   g := x -> add(h(n) sin(n x), n = 1 .. 4)
   g(x)

result in

   sin(2 x)

which is what I expect.  However, the command

   evalhf(g(2))

results in the error message
   "Error, unable to evaluate function `int` in evalhf"
so evalhf is not being passed sin(4) as I want....

I am new to Maple and trying to use it for a school project. I actually have this section of code written in a textbook and I want to use Maple to solve and plot this predator prey model. Here is what I have, Im not sure why it won't work any help will be geatly apprciated.

> e1 := diff(e(t), t)-0.325e-1*e(t)+.8*e(t)*w(t);
> e2 := diff(w(t), t)+.6*w(t)-0.5e-1*e(t)*w(t);
> sys := {e1, e2};
> ic := {e(0) = 18.0, w(0) = 0.21e-1};
> ivp := `union`(sys, ic);

I'm filling an array of functions like this:

below code is calculate basis of kernel and kernel

i guess basis of image is 

remove(has, Ga, [r,u,v,w]); if this correct, i eliminate this, i can get the image

however it include variable 'a'

is it correct? if not, how to calculate? 

my final goal is to make unexact sequence into exact sequence

Hi

I am trying to do a phase plot of an autonomous system using DEplot command. However, no phase plot appears. Could you tell me what am I doing wrong? The same code worked for my professor in class, but it's not working for me. I am using Maple 16. The code is posted below.

> with DEtools

> sys := diff(x(t), t) = y(t), diff(y(t), t) = x(t)*(1-x(t)*x(t))+y(t);

> DEplot([sys], [x(t), y(t)], t = 0 .. 0.1e-8, x = -3 .. 3, y = -3 .. 3, color = black)

Dear All,

evalf(RoofOf(Z^6-3*Z^4+3*Z^2+Z-1,index=real[2]) fails to deliver a numerical value.

1. I can use fsolve to compute the real roots but I need to replace all the occurences of RootOf by its numerical value in lengthy expressions.
2. Also simplify(RoofOf(Z^6-3*Z^4+3*Z^2+Z-1,index=real[2],RootOf) does not work.
3. I read the other posts related but could not find any answer.

Thanks for any help,

S.

  Hey,

 I am using maple to do some numerics (bound to use it instead of mathematica because of university guidelines) and my problem is that as the plotting options of maple are a bit unsatisfactory I need to export my data. This has worked fine so far using the writedata-command while I was working on normal (10 digit) precision. Now however I need to increase the precision and to my dismay writedata just cuts everything after the normal 10 digits away and...

I came across a plot3d where a non continuous function looked continuous. One way to confirm if it was indeed coninuous was to use style=point

with(plots):
plot3d(Im(sqrt(x+I*y)), x = -2 .. 2, y = -2 .. 2)

plot3d(Im(sqrt(x+I*y)), x = -2 .. 2, y = -2 .. 2, style = point, grid = [70, 70])

Hi everybody,

I have a follow problem:

Maple offers generate graph (network) for example in this way:

G:=Graph({{1,2},{1,3},{2,3}})

where  {{1,2},{1,3},{2,3}} is a list of edges.

In my study I need to generate a big graph (network), where list of edges is very long 
(contains more than 100000 edges).
Can I import from my directory (for example C:\\Desktop\) file, contains edges.
Now I copy from txt file all list of...

Several months ago, I'd posted a two-letter-words quiz and a two-to-make-three quiz meant for fans of the Scrabble game. Here is a third worksheet that tests your ability to find anagrams of seven-letter words. The worksheet is structured around six-letter stems and the lists of seven-letter...

with(ScientificConstants):

GetElement(Ra,atomicweight);

Hello,

I want to pick 3 random(ish) points from a 3D plot for using in an iterative scheme. 

Is there a way of doing this by just clicking the plot and getting the (x,y,z) values for the specific point or is it something more complicated?

Thanks,

Rachael

We have a set S of 30 elements and choose its subsets A, B, and C such that nops(A union B) = 5,  

nops(A intersect B intersect C) = 3. How many ways are there to produce that?

How to count this number  with Maple?