Hello,

I have trouble in using the function factors. For example, I expect

factor(Pi*(t^2+1), {I});

to output

-Pi*(-t+I)*(t+I)

but instead the result is

Pi*(t^2+1)

This problem does not appear if Pi gets replaced by a general symbol:

factor(pi*(t^2+1), {I});

produces (as I expect it should)

-pi*(-t+I)*(t+I)

The problem seems to be tied to symbols representing constants, as for example replacing Pi by Catalan also results in no factorization being performed. It further seems to be tied to specifying a splitting field, because

factor(Pi*(t^2-1));

results in

Pi*(t-1)*(t+1)

Is this behaviour intended? Probably the reason is that the polynomial does not have algebraic coefficients (as it includes Pi). Indeed,

factor(Pi*(t^2-1),{});

produces the error message

Error, (in factor) expecting a polynomial over an algebraic number field

But why does this error then not appear for the call factor(Pi*(t^2-1))? If this would assume complex coefficients, it should factor using I. Considering coefficients in an algebraic number field, also the original call factor(Pi*(t^2+1), {I}); should raise an error!?

Thanks,

Erik

intsolve(int(f1(u)*(x-y), u = a .. b) = (12)*cos(x)+5*x^2-12, f1(x));I try to resolve the integral equation but i received all the time the followinf message error 

Error, (in intsolve) invalid input: rhs received {f1(x) = ?}, which is not valid for its 1st argument, expr
I try to use different form but i do not how to resolve the help center do not help to much.

I preciate any help thanks

Which book is the starting point and have examples

I am trying to produce an animation. Everything seems correct, but the evaluation is taking a very long time. Even after an hour, it still tries to crank out a graph for me. I even tried to truncate the integral!

Here is my code.

with(plots):

z:= x -> 2*(int((sin(2*y)-sin(y))*cos(y*x)*exp(-y^2*t)/y, y = 0 .. 200))/Pi;

animate(plot, [z(x), x = 0 .. 10, y = -.1 .. 2], t = 0 .. 1, frames = 100);

Would could be the problem? 

Hi all

How to read a value from keyboard of PC when executing a maple document and assign it to a variable ?

Thanks

> with(DEtools);
> L := -1.576674; MU := 0; DE13 := {(D(x))(t) = x(t)*(1+4*x(t)*x(t)-y(t)*y(t))+MU*y(t)*(x(t)*x(t)-.43*y(t)*y(t)-L), (D(y))(t) = y(t)*(1+x(t)*x(t)-.5*y(t)*y(t))+MU*x(t)*(x(t)*x(t)-.43*y(t)*y(t)-L)}; DEplot(DE13, [x(t), y(t)], t = 0 .. 20, [[x(0) = 0.1e-1, y(0) = .99], [x(0) = -.1, y(0) = -.9], [x(0) = 1.1, y(0) = 0], [x(0) = 0, y(0) = .2], [x(0) = 0, y(0) = .6], [x(0) = .6, y(0) = 0], [x(0) = .75, y(0) = 1], [x(0) = .1, y(0) = .1], [x(0) = .5, y(0) = 1.0], [x(0) = -.5, y(0) = 1], [x(0) = .5, y(0) = -1], [x(0) = -.5, y(0) = -1], [x(0) = -0.1e-1, y(0) = .99], [x(0) = 0.1e-1, y(0) = -.99], [x(0) = -0.1e-1, y(0) = -.99], [x(0) = .5, y(0) = -1], [x(0) = -.5, y(0) = -1], [x(0) = 0.1e-1, y(0) = .9]], stepsize = 0.1e-1, scene = [x(t), y(t)], title = "phaseplane 3 prime plot", linecolor = black, thickness = 1);
-1.576674
0
/ / 2 2\
{ D(x)(t) = x(t) \1 + 4 x(t) - y(t) /,
\

/ 2 2\\
D(y)(t) = y(t) \1 + x(t) - 0.5 y(t) / }
/
Warning, plot may be incomplete, the following errors(s) were issued:
cannot evaluate the solution further right of .93908020e-1, probably a singularity
Warning, plot may be incomplete, the following errors(s) were issued:
cannot evaluate the solution further right of .26367741, probably a singularity
Warning, plot may be incomplete, the following errors(s) were issued:
cannot evaluate the solution further right of .23463732, probably a singularity
Warning, plot may be incomplete, the following errors(s) were issued:
cannot evaluate the solution further right of 1.7040014, probably a singularity
Warning, plot may be incomplete, the following errors(s) were issued:
cannot evaluate the solution further right of .62484768, probably a singularity
Warning, plot may be incomplete, the following errors(s) were issued:
cannot evaluate the solution further right of .62484768, probably a singularity
Warning, plot may be incomplete, the following errors(s) were issued:
cannot evaluate the solution further right of .62484768, probably a singularity
Warning, plot may be incomplete, the following errors(s) were issued:
cannot evaluate the solution further right of .62484768, probably a singularity

what do i need to do so there are no more singularites?

i cant find the error the program is saying i have 

> L := -1.576674; MU := 0; DE13 := {D(y)*t = -x(t)*(1-2*x(t)*x(t))+MU*y(t)*(x(t)*x(t)-3*y(t)*y(t)-L), (D(x))(t) = y(t)*(1-y(t)*y(t))+MU*y(t)*(x(t)*x(t)-3*y(t)*y(t)-L)}; DEplot(DE13, [x(t), y(t)], t = -20 .. 20, [[x(0) = 0.1e-1, y(0) = .99], [x(0) = 0.5e-1, y(0) = .95], [x(0) = .1, y(0) = .9], [x(0) = 0.4e-1, y(0) = .96]], stepsize = 0.1e-2, scene = [x(t), y(t)], title = "phaseplane plot", linecolor = black, thickness = 1, number = 1000);
 
Error, (in DEtools/DEplot/CheckInitial) too few initial conditions: [x(0) = 0.1e-1, y(0) = .99]

it might be hard to read but if someone could help me it would be very appreciated 

For some time I have been running into the problem where uploaded worksheets that are inlined into a Mapleprimes post get gridlines shown, even when they are not specified or shown in the original worksheet. This is a problem because quite often the gridlines make an inlined plot unattractive.

I believe that Mapleprimes uses some version of MapleNet as a mechanism for inlining uploaded worksheets.

It seems that the Standard GUI and/or MapleNet have special handling for gridlines in the sense that they actually distinguish between PLOT structures generated without the `gridlines` option versus those created with `gridlines=false`.  I believe that this has something to do with the persistence of various plot qualities in an output region which (perhaps for historical reasons?)  allow re-execution of a plot input command to produce a plot output rendering that remembers whether gridlines are visible.

If the second plot below does indeed get rendered here in Primes without gridlines visible then one workaround is evident: adding `gridlines=false` instead of omitting the option.

Download test.mw

I'll submit a bug report against MapleNet.

acer

Hello,

I am having trouble using the programmer entry point interface to convert/parfrac. As an example consider : While

> convert([x, [I*(x+I), 1]], parfrac, x);                   

         [-I, [(I + x) I, -I]]

correctly computes a partial fraction decomposition, the equivalent input

> convert([x, [I*x-1, 1]], parfrac, x);  

results in the error message (both in Maple 16 and 17)

Error, (in convert/parfrac) denominator factors must be coprime

which does not make any sense to me, since there is only a single denominator factor present (and it is even the same factor as in the previous call, only written differently).

What is the reason for this behaviour and how can I use convert/parfrac in a way that avoids such errors?

Thanks,

Erik

Hello

I'm doing some calculation reports in maple. These reports are to be submitted to various classification societies - which all have different requirements to the calculations.

I would like to make a report, where the class specific calculations would be append based on a selection of class in the main calculation.

How do I do this?

If I was using latex, matlab, APDL or something like that, I would do and *IF Class=class1, *INPUT class.calc, *ENDIF, but how to do this in maple?

Hi

I need a temperature distribution inside a barrier during a heating process.
I will be appreciated for any help.

wz

Download heating.mw

Hi

I use Maple perhaps only one time per year and thus i'm a beginner with the product (even if i use it since 1996). I'm trying to make the following script work in Maple 17:

http://www.maplesoft.com/applications/view.aspx?SID=4268&ref=Feed&L=F

but i fail.... Some help will be appreciate

restart:

Eq1:=1/r*diff(r*diff(w(r),r),r)-(cos(z1))^2*(w(r)+1)-DP;

dsolve({Eq1});

bcs:=D(w)(0)=0,w(r2)=A1;

dsolve({Eq1,bcs},w(r)):

where z1, Dp, r2, A1 are constants.

Hi, can I get some help with this?

The question is:

Consider the following IVP for a mass of m = 2 kg attached to a spring with a spring constant k = 9 N/m. The spring mass system is in a medium with damping constant b.

2y" + by' + 9y = 0

y(0) = 0, D(y)(0) = -3 

It then asks find three values b1, b2, b3 where b1 is underdamped, b2 is critical, b3 is over. 

I set b1 as 1, b2 as sqt 72, b3 as 9. 

Then it asks to find the quasi period. 

I can't get my quasi period right. My answer is 2pi/ sqrt (4.5).

Any help?  

Hi.

Please, I need a code in maple for adaptative setp size control for runge Kutta.

Thank you.