i am using maple to solve a system of ordinary differential equations , 3 unknows (x,y, x ), and 3 equations (dx/dt,dy/dt,dz/dt)

there is one known variable denpendent on x and z

# code begins here

if x(t) <= z(t) then Q(t) := 8 end if;

if x(t) > z(t) then Q(t) := 10 end if;

eq1 := diff(x(t), t) = 3*x(t)-1;

eq2 := diff(y(t), t) = y(t)+Q(t);

eq3 := diff(z(t), t) = z(t);

eqs := {eq1, eq2, eq3};

# code ends here

above i put the system of ODEs, the code maybe illegal in maple, but i wrote in this way to make it clear.

Q is dependent on x and z.

in the past, when i was trying to solve ODEs, normally, eqs contains with only x,y,z as unknowns. but in this eqs, clearly, Q is included as an unknown. 

i've tried to use piecewise function to express Q(t), but failed.

how could i solve a system like this? thanks 

Hi,

how can I solve a set of first order, coupled, non-linear and inhomogeneous differential equations using MAPLE 12.

In the old version of Maple, the accurate value of Sin()and Cos() at some particular points, such as Pi/10, can be returned as below:

But in Maple 18, it just returns the same as the input.

How to make Maple18 return the accurate value as before?

i have a large angle and i wish to represent this angle called theta in the range [0 2*Pi]. In matlab this is done by the command mod(theta, 2* Pi). ihave tried frem and mod in maple but the two cannot accept 2*Pi as a second argument 

how can i do that 

Here is the ODE:

dsolve((y(x)^2-x)*(D(y))(x)+x^2-y(x) = 0, {y(x)})

And the Maple 18 returns a very complex result.

But as we know,the more elegant result should be this:

How can I get this simple result with Maple?

Take a look at this link.

Hello,

I would like to solve easily this equation with maple.

When i use solve or isolate functions, i have a result with arctan function.

"sol := solve(a*cos(gamma)+b*sin(gamma)+c, gamma):
isolate(a*cos(gamma)+b*sin(gamma)+c=0,gamma); "

It is good but i would like solutions with arccos.

In other words, i would like to have these calculations :

a*cos(gamma)+b*sin(gamma)+c=0

cos(psi)=a/sqrt(a²+b²)

sin(psi)=b/sqrt(a²+b²)

thus 

cos(psi)*cos(gamma)+sin(psi)*sin(gamma)=-c/sqrt(a²+b²)

cos(psi+gamma)=-c/sqrt(a²+b²)

gamma=-psi -/+ arccos(c/sqrt(a²+b²))

Is there a possibility to lead this calculation automatically with maple? For example, is it possible to force isolate function to seek for this kind of solution.

Thanks a lot for your help

Hello,

I often need to copy equations from maple with mathml option so as to copy it in my equations in mathtype in microsoft word.

Unfortunetaly, for a bit long equation, i often have troubles et i can't copy it in my mathtype equations.

Have you some ideas so as the copy in mathtype equations runs everytime ?

Thanks a lot for your help

Hi MaplePrimers,

I've written a function that needs to be evaluated at a bunch of different points.  Evaluating it in a loop works. I'm wondering if there was a faster way to do this because I'm evaluating a list of 400k+ sets of points.  

Right now I'm using a loop with the following code.

for i from 1 to 500000 do 
     Results(i):= f(L[i][])[1];
od;

 

If I have a function f, which has 5 arguements, f(y, w, x,y,z).

I also have a list of those arguements:  L = [[1,2,3,2,3],[4,5,6,2,3],[7,8,9,2,3]]

What would be the fastest way to get a list of results?  Also, is there a way that I could preallocate memory for this list?

Ideally, I would like to get the output as as list.  ie:

Results:= [[f(1,2,3,2,3)], [f(4,5,6,2,3)], [f(7,8,9,2,3)]]

Hi all,

As we know that the differential of conjugate(z) is non-analytic.

But it seems that the diff gives the solution about the complex function conjugate(z)

What does it mean?

Hello guys, i have a system of equations ( dynamical system ) which i have its critical points but when i compute its critical points with maple i get different points , i dont know what is wrong . thank you for your time.

critical.mw

Is there any one to help me in calculating computational order of convergence of derivative free method. I am trying to calculate programs runs with immature error and does not print it.

Please is there any 1 to help.

Hello

Is it not possible to view page breaks in ypyr document in Maple? 

It will make it easier to at up at nice document??

Jakob

Hi! I'm trying to make a point plot and they must have different colors, like the CIE diagram. I wish they varied from red to blue in 31 steps, as shown in the picture (they are all black :\). Does anyone have any idea how to do this? The red line is for something else.

This the code for the dots:

Using maple 16. When I run a worksheet it adds in extra rows of the red >s. The attached example was run 3 times. How do I stop this happening?

Download worksheet_issue.mw