Hi,

I am using Maple 13 (hoping to upgrade soon) under Windows 7.

The open file dialog looks a bit weird, as per the illustration. Is this a known bug, and has it been fixed up in subsequent versions of Maple ?

thanks,
Andrew

Up until now, I have been using lists instead of sets in solve() in order to ensure the first equation is solved for the first variable, the second for the second, etc.  However, I have run into a case for which using an equation list and a variable list does not work, but the equation list alone is fine, and sets of both are fine, etc.  I would be grateful if somebody can explain why the first statement below does not produce a solution.

> soln := solve([foc1 = 0, foc2 = 0, foc3 = 0...

At one step of my code I need to define an array of functions which I will later use.

Simplified version of it to highlight the problem:

restart:with(linalg):
procG:=proc(a,b) if a>b then a-b else 0 end if end proc:
F:=vector(2):
for i from 1 to 2 do F[i]:=x->i*procG(x,0) end;

In the actual code array is much bigger and the expression for each function is much more complicated so using the cycle is a real 'must'.

Instead of F[1...

Hey,

i have 2 differential equations and want to solve the first one when x is positive and the second when x ist negativ. For this problem i wrote the follwing procedure. But when i try i have the posted error. Has someone a good idea to help me?

Thanks a lot

> DGL3 := 10*(D(D(x)))(t) = x(t);

> DGL4 := 10*(D(D(x)))(t)+5000 = x(t);

Tsolver:=proc()
global DG1, DG2, func, var, var_min, var_max, x, Dx, N:

I need to determine the general solution of the system of differential equations.

System of equations:

dx/dt = 2x-2z

dy/dt = 2y+2z

dz/dt = -2x+2y+4z

Thanks for the help!

for example:

>>simplify(cos(i)*sin(u)/sin(i),trig)

                    cos(i)*sin(u)/sin(i)

Maple do'not  simplify cos(i)/sin(i)=ctan(i) atomaticly.

also  half angle formulas:

>>simplify(sin(i)/(cos(i)+1),trig)

           sin(i)/(cos(i)+1)

i want to get tan(i/f)

I have an ODE to solve that looks like this: 

((diff(R(r), r, r, r, r))*r^4+3*(diff(R(r), r))*r-3*(diff(R(r), r, r))*r^2+2*(diff(R(r), r, r, r))*r^3-3*R(r)+4*R(r)*n+2*R(r)*n^2-4*(diff(R(r), r))*r*n+2*(diff(R(r), r))*r*n^2+4*(diff(R(r), r, r))*r^2*n-2*(diff(R(r), r, r))*r^2*n^2-4*R(r)*n^3+R(r)*n^4)/r^4 = (-108-1362*n+2122*n^2+2019*n^3-3032*n^4+401*n^7+1192*n^6-1033*n^5-25*n^9+6*n^10-180*n^8-4128*r^(n+3)*n^3+2304*r^(n+3)*n-576*r^(n+5)*n-760*n^6*r+575*n^5*r-244*n^7*r-2108*n^3*r-11616*r^(n+3...

old version define use
'homalg/default':=RPI;

in maple 15
libname := "D:/homoalg/10_homalg.lib",libname:
with(homalg):

> define(homalg, RPI, 'default');
Error, (in define) homalg is assigned
> hom2 := Hom(L, K, var);
Error, (in homalg/tablename) Since homalg/default is not defined, the last argument must be a table containing the (minimum) homalg conversions or an unassigned symbol pointing to such a table!
> define(homalg, 'RPI', 'default');

Maple 13

hmm... I don't really understand the diference between a question and a post, but here goes.

I homeschool my two grandchildren in the 8th and 10th grades. they are not taking calculus or precalc yet. Lately we have been studing systems of equations. what I used to call simultaneous equations. We find the x-y intercepts and plot them. We also work backward and find the equation from the intercepts.

My question is this: Is there a built-in function such as Built-in-Function([0, 4...

how can I solve this equation

I want to solve numerically the nonlinear problem 

a*(diff(y(x), x, x))+2*(diff(y(x), x))+exp(y(x)) = 0, y(0) = 0, y(1) = 0

by defining my own method defined as 

y_n+1=y_n+2*h*(-2*y_n+2*ln(2/(1+x))-(1/2)*a)^2/(a*(-4*y_n+4*ln(2/(1+x))-a-h*(4*y_n-4*ln(2/(1+x))+a+x+1)/a))

where h is the step-size. Please help me by letting me know how can I do this using Maple 11.

Hi!

My problem is that MapleSim refuses to use my interpolation table, and the simulation stops, because it says the first column is not in ascending order. Seems easy to solve, but it is not! The column IS in ascending order, I even arranged it several times in Excel. I can't figure out what is the problem.

If someone has time, I attached the interpolation table.

Best regards; e6.xlsx

Hey there i try to solve this system of equations. It is required that the left side of the equation only take positive values. Has someone an idea to fix this solution or has maybe another idea to help me.

> m[1] := 30; c[1] := 48000; c[0] := 20000; d[1] := 21; d[0] := 70;

> DGL1 := m[1]*(D(D(x)))(t)+d[0]*(D(x))(t)+d[1]*(D(x))(t)+c[0]*x(t)+c[1]*x(t)+50000 = -(1/1000)*c[1]*S-(1/1000)*d[1]*DS*((1/60)*(2*Pi*250))-(1/1000)*m[1]*DDS*((1/60)*(2*Pi*250))^2;