Dear Primers

I have an exponantial equation of the form below:

eq161 := 1/2*alpha^4*(-2*exp(-1+1/2*(4*alpha^2+1)^(1/2)+1/2*(-4*alpha^2+1)^(1/2))*(4*alpha^2+1)^(1/2)+2*exp(-1+1/2*(4*alpha^2+1)^(1/2)-1/2*(-4*alpha^2+1)^(1/2))*(4*alpha^2+1)^(1/2)-2*exp(-1+1/2*(4*alpha^2+1)^(1/2)-1/2*(-4*alpha^2+1)^(1/2))*(-4*alpha^2+1)^(1/2)+2*exp(-1-1/2*(-4*alpha^2+1)^(1/2)-1/2*(4*alpha^2+1)^(1/2))*(-4*alpha^2+1)^(1/2)+2*exp(-1+1/2*(-4*alpha^2+1)^(1/2)-1/2*(4*alpha^2+1)^(1/2)...

I have been trying to obtain a 3D plot of f9x,y)=(x+y)e^(-x^2-y^2) and it keeps outputting  "warning unable to find numerical values for the in the region....blah blah blah"

Here is my call sequence

> plot3d((x+y)*e^(-x^2-y^2), x = -1.7 .. 1.7, y = -1.7 .. 1.7);
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

Anyone know what to do? ...

Can I install both 32 and 64 bit version on one PC? (64 bit in Program Files and 32 bit in Program Files (x86))?

If so, does it mean  I will need to use a second license? Not a problem, my Office version is 32 bt and have Maple 64 bit installed and I want to use Excel.

Hi

I am trying to do an animate plot of the Lorenz System, so that it appears as time progresses.

I have solved the equations numerically using rkf45 (using a code i found somewhere else, not taking credit for that! This is the code i used to solve it http://people.oregonstate.edu/~peterseb/mth480/docs/lorenz.pdf) and now i wish to plot the solution evolving over time using animate.

That is, something that will plot a bunch of rectangular boxes in 3d, instead of a bunch of rectangles in 2d.  Thank you.

Download problem_for.mw

I use some codes to find the coefficients of given functional expressions. But in the procedure of operation, "Error, invalid 'if' statement" is showed. How can I do to solve the error?
If this structure of code can't find the coefficients, how to get the coefficients?

P.S. the coefficients of given functional expressions like this:

given Ex:=a*x+b*y-d*z+e*y-f*x-m*z,

let say I have a rod(x-direction) with a mass at each end. I want to apply two different forces(both z-direction) to the ends of the rod. Also, i want the force to be always perpendicular to the rod length. The rod is supposed to be spinning. However, the rod only move at the speed due to the larger force.

How can I make the rod to be spinning(each end move at different speed)?

And, how to use the solid green(flange A)? I am very curious about this asI believe...

When using the command "for", the results are placed in a column,such as if we input
for i from 1 to 3 do  i end do, the results are showed as

1

2

3.

This style is not convient to use for following computation. So how to put all results into a list or set ?

Can anybody explain why the same dsolve-command gives the correct results in Maple 13 and an unexpected complex result in Maple 15?:

Download problem1.mw

Give a polynomial a*x+b,We can use the command "coeff" to get a coefficient of x. Unfortunately the command does not work for functional work. I have a comlicated functional expression, and want to get the coefficients of some given basical term. How can I do to get the coefficients?

arclengthtrig.mw

Each time I try to appriximate it 5 decimal places it returns something else.

f(x):=((e^-ax^2)-bxln(1+x^2))/(2+x^2+csin(Pi*x))

i have defined a,b and c. (all randoms numbers between 0 and 1 )

But when i try to plot it

plot((f(x)), x=-4..4) i get ( warning unabe to evaluate function to numeric values ion the region)

also i can plot the graph even without a range included ???

What am i doing wrong, have i defined f(x) right. thanks in advance

also i can plot the graph even without a range included ???

I have a peace of a programm of finding the shortest way in graph! And I need to animate this way! Help please! 

This is a code of programme:

> restart: with(networks):
> new(G): n:=6:
> addvertex(i$i=1..n,G); 
1, 2, 3, 4, 5, 6
> addedge([seq([i,i+3],i=1..3),[1,2],[2,3],[4,5],

> [5,6],[1,5]],weights=[12,16,20,11,15,13,14,26],G):
> draw(Linear([1,4],[2,5],[3,6]),G);

 > T:=shortpathtree(G,1):

Besides of other things i should also analyze what happens with function at y=0. For now IntermediateCalc incapsulates limit but it too slow. What can you suggest better? Tried series but there is the problem that function is only defined at right of 0, there is no expansion in this case. See attach for deatails. main.mw

Hello,

I set up 8 equations systems with 8 variables (multivariate polynomial equations, which are product of maximization problem with budget constraint). The equations are set as eq1, eq2, etc as attached in the file. However, the  "fsolve" function can't give me any solution. Can someone recommend me a way that will solve the equations.

 model_4_countries_03.mw