In the following script, I am trying to understand why evala returns an error. It returns

                Error, (in evala/Reduce/nf/indep) invalid arguments to coeffs

in a couple of places. I tried, and I can get around the errors by doing it a complex way, but it seems like I'm just not using evala correctly. Perhaps someone can comment? I'd very much appreciate it.

Hello,

tryning to put some text on plots,

and wonder how can I separate text decoration of variables.

For example a circule with radius

and center in

,

Is it possible to programmatically insert an embedded component, say for example a TextArea0?

    Why the zeta1 does not plug in numerical calculation.
 My program:

restart:
>
> h0:=0.156;
> d:=0.32*h0;
> l:=1;
> h1:=h0-d;
> h2:=h0+d;
> h5:=evalf(2/3*h0);
> h7:=h0;
> s1:=evalf(2/3);
> s2:=evalf(2/3);
> g:=9.8;
> d1:=1;
> Term:=10;
> Num:=5:
> n:=1:
>
>
> for N from 1 to Num do
> k0:=evalf(0.5*Pi+2*(N-1)*Pi/(Num-1)):

hello, everyone,
the attached pdf file contain four models, I can't get the solutions of last three models.
help, thank you in advance.

123.pdf

The damped driven pendulum is modeled using :

d²(x)/d(t²) + b*d(x)/d(t) + sin(x) = F*cos(x).  (4)

Numerically simulate (4) with b=0.22 and F=2.7

a) Starting from any reasonable initial condition, perform a phase portrait analysis. Show that the time series has an erratic appearance, and interpret it in terms of the pendulum's motion.

b) Plot the Poincare section by sampling the system whenever  t=2*pi*k, where k is an integer.

 d^2(x)/d(t^2) + sin(x)=0  (1)

d^2(x)/d(t^2) + x = 0 (2)

d^2(x)/d(t^2) + ( x - (x)^3/6) = 0 (3)

1) Compare the results of numerical simulations of (1), (2), (3) to see how closely the period of the periodic orbits relate.

a) Perform a phase portrait ( (x)'(t) vs. x ) analysis for (1), (2), and (3).

b) Consider the initial conditions x(0)= x₀ and x'(0)=0. For what intervals of x₀ do the periodic orbits of (2...

For example, how to round 45.67845 up to 3 digits after comma?

expected answer - 45.678

Hi

Can I have an example of inverse dynamics?

Thank you,

Hi there,

can Maple simplify expression

x[1]+x[2]+x[3]+x[4]+x[5]

to

sum(x[i],i=1..5) ?

Or

cos(y[1])+cos(y[2])+cos(y[3])+cos(y[4])+cos(y[5])

to

sum(cos(y[i]),i=1..5)

Its hard to find every such sequences in big equation, so Maple can help may be.

Hi everybody. Firstly, i apologize for my poor level of english. I am a new maple user and i want to solve the following system, but I face some difficulties. I go through forum, FAQ, courses notes on the net and so on but I don't find the solution. 

I first define the folowing equations:

Hi,

I'm using the DirectSearch package in a 10 periods model and in the first period i get this values:

"

> DirectSearch[SolveEquations](sys, assume = positive);
Warning, complex or non-numeric value encountered; trying to find a feasible point
        [HFloat(1.1842542076623546e-32), 

          Vector[column](%id = 18446744078126621390), [

          x1a = HFloat(4204.651582462925), 

          x1c = HFloat(4204.651582462925), 

Good morning everybody,

I have to make the Inverse Laplace Transformation of a function which is too complicated and the only way I have is to make it from the points of the function (I can get a plot but maple cannot get the formal form of the function because it is just too big). Does a numerical method exist in maple which can make the Inversion only from the points of the function?

Thank you,

ssteve

How to plot x versus theta of the following implicit function

sin(theta)-2*sin(2*x-theta+(1/3)*Pi)/sin(x+(1/3)*Pi-theta)=0

where x is the implicit function of theta

now how can I plot the relationship between x and theta(condition:-Pi<theta<Pi,-Pi<x<Pi)

How to simplify the following trigonometric expression

sin(w t-theta)+sin(w t-theta-2pi/3)-sin(w t-theta+2pi/3)

to

-2cos(w t-theta+pi/6)