## Maple cause error but doesn't show the reason...

I am coding a big module to solving my project : analyze function in math, but when I compile my module maple return "Error," but it doesn't tell me what error happened.

I check the maple help and it said:" If no msgString is given, error raises the most recently occurring exception" but I have no exception before.

This is the pic of that error.

## How can plot3d a sub-surface from surface ?...

Hi, everybody.

I have a problem when I try to plot3d a sub-surface from a surface as follows:

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 > p:= proc(u,v) if u
 > h:= proc(u) 2*u  end proc:
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sub-surface.mw

Thanks and have a nice day.

## Kinematics using syntax in Maple

Maple 18

In this file you will be able to observe and analyze how the exercises and problems of Kinematics and Dynamics are solved using the commands and operators through a very well-structured syntax; Allowing me to save time and use it in interpretation. I hope you can share and spread to break the traditional and unnecessary myths. Only for Engineering and Science. Share if you like.

In Spanish.

Kinematics_using_syntax_in_Maple.mw

Lenin Araujo Castillo

## Integral of complex function ...

I need to calculate the following complex integral:

oint_C { [(z^4exp(2z)+1)/(z+i)^3] - [(z^3+z)/{(z-2i)(z-5)}] + 8*Pi*exp } dz,

Where C is the circumference |z-1| = sqrt(11/2), positively oriented.

Someone can help me, I already researched but I can not integrate.

## An error in if statement...

Dear all,

I use the following statment (without numerical values)

if        IT<20     then        IT:=IT+1

if    ZUM<(0.1)^(8);    IT=20;         else;

for i from 1 to 10   do                               YU[i]:=U[i];                  od;

for i from 2 to 9 do                           DU1:=YU[i+1]- YU[i-1];        od:

end if;

ZUM:=U[1]-YU[1];

end if;

the following error occur

where is the problem.

## Error, (in plot3d) bad range arguments:...

Can't understand what's wrond. This text from my academic books but it doesn't work on practice. Help please

plot3d(polygons([[0, 0, 0], [1, 0, 0], [1, 0, 0], [0, 1, 0]], [[0, 0, 0], [0, 1, 0], [0, 1, 1], [0, 0, 1]], [[1, 0, 0], [1, 1, 0], [1, 1, 1], [1, 0, 1]], [[0, 0, 0], [1, 0, 0], [1, 0, 1], [0, 0, 1]], [[0, 1, 0], [1, 1, 0], [1, 1, 1], [0, 1, 1]], [[0, 0, 1], [1, 0, 1], [1, 1, 1], [0, 1, 1]]), light(0, 0, 0.0, 0.7, 0.0), light(100, 45, 0.7, 0.0, 0.0), light(100, -45, 0.0, 0.0, 0.7), ambientlight(.4, .4, .4), title(cube), style(patch), color(zhue));

Error, (in plot3d) bad range arguments: light(0, 0, 0., .7, 0.), light(100, 45, .7, 0., 0.)

## Help with Maple Commands...

Hi I was wondering if you can help me with some maple commands about using Euler's method. My professor created a tutorial on using some commands to calculate the value via Euler's method.

Her commands in the tutorial for using Euler's method  for a differential equation- dy/dx= x+y   y(0)=1

x0:=0:y0:=1:xf:=1:n:=10:

h:=evalf((xf-x0)/n);

f:=(x,y) -> x+y

x:=x0:y:=y0:

This next step confuses me the most, my professor uses this syntax to compute the values of approximation via Euler's method. N represents the number of pieces we want to approximate the value with. X0 is initial and XF is final.

forifrom1tondo k:=f(x,y):y:=y+h*k:x:=x+h:print(x,y):od:

I tried replicating this syntax on the exact same problem, copying the syntax commands word for word. Yet, I keep getting the same error "unable to parce" error, with the "od" being highlighted. But on her tutorial, it gave her an two columns with the intervals (n) and all it's values. She even did the same did for only wanting 1 loop printed

forifrom1tondo k:=f(x,y):y:=y+h*k:x:=x+h:od:print(x,y):.   And it gave her only 1 loop.

## Maple programing problem in for loops...

helo my friends,

## computing the wronskian with Maple gave nothing...

I am tying to compute the wronskian of a fourth order DE: y=C1e2x+ C2e-x +C3xe-x+ C4x2e-x Here's what I did:

with(VectorCalculus):
with(LinearAlgebra):

Determinant(Wronskian([e^(2*x), e^(-x), xe^(-x), x^2*e^(-x)], x)):

which gave nothing.

AJ

## How to extract Real and Imaginary using assumption...

I can't get the Real and Imaginary parts of matrix to seperate out as required. It is an SU(2) matrix. Want to convert is to a 4 Vector (quaternion). I think because Maple doesnt know what psi(t) is being conservative so to speak. Tried assume, assuming...

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 (2)

 (3)

## What is my mistake in this simple code?...

Where I made a mistake I got this error in for loop and how to fix it?

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## Problem with functions...

i got this code, but for any n = 2N (par) i get some high errors, my M goes nuts.  anyone knwos wheres my mistake?

With(CurveFitting); Digits; 5; f := proc (x) options operator, arrow; abs(x) end proc; n := 8; h := 2/n; for i from 0 to n do x[i] := h*i-1 end do; for i from 0 to n-1 do L[i] := (product((x-x[j])/(x[i]-x[j]), j = 0 .. i-1))*(product((x-x[k])/(x[i]-x[k]), k = i+1 .. n-1)) end do; lagr := sum(f(x[p])*L[p], p = 0 .. n-1); P := expand(lagr); plot({P, f(x)}, x = -1 .. 1, y = 0 .. 2); M := maximize(abs(abs(x)-P), x = -1 .. 1); M1 := numapprox:-infnorm(abs(abs(x)-P),

x = -1 .. 1)

## My system of equation was ODE, but Maple insists i...

I was trying to solve a system of ODE using Maple, but to my surprise, Maple recognizes diff((phi(t), t)) as a variable which is different than t.

My code is as following:

dsys := {2*m1*(a+l*sin(phi(t)))^2*(diff(diff(theta(t), t), t))+4*m1*(a+l*sin(phi(t)))*l*cos(phi(t))*(diff(theta(t), t))*(diff(phi(t), t)) = M, 2*m1*l^2*(diff(diff(phi(t), t), t))+4*m2*l^2*sin(2*phi(t))*(diff(phi(t), t))*(diff(phi(t), t))+4*m2*l^2*sin(phi(t))^2*(diff(diff(phi(t), t), t))-2*m1*(a+l*sin(phi(t)))*l*cos(phi(t))*(diff(theta(t), t))*(diff(theta(t), t))-2*m2*l^2*(sin(2*phi(t)))(diff(phi(t), t))*(diff(phi(t), t)) = -(2*(m1+m2))*g*l*sin(phi(t))-2*k*l^2*sin(2*phi(t)), phi(0) = 0, theta(0) = 0, (D(phi))(0) = 0, (D(theta))(0) = 0}

subs({M = 10, a = .5, g = 9.81, k = .1, l = .5, m1 = 10, m2 = 1}, dsys);

dsn1 := dsolve(dsys, numeric)

The error I got was Error, (in dsolve/numeric/process_input) input system must be an ODE system, got independent variables {t, diff(phi(t), t)}

I don't get why this is happening. Could you show me what's going on?

## How do I generate the recursion...

Please Sir/Ma, I'm trying to generate a recurrent relations of this series and I try to use "if" "else" condition but I didn't get it right. Any one with useful suggestions. Appreciate

restart;
Y[0] := A; Y[1] := B;
if k = a then delta(k-a) := 1 else 0 end if;
0
for k from 0 to 10 do Y[k+2] := solve(add(delta(i-1)*(k-i+1)*(k-i+2)*Y[k-i+2], i = 0 .. k)+add((delta(i)-delta(i-1))*(k-i+1)*Y[k-i+1], i = 0 .. k)+lambda*Y[k] = 0, Y[k+2]) end do;
y := sum(Y[j]*x^j, j = 0 .. 10);

## an error occurred, diff received 0...

Hello, I have a function defined as

g :=  (x, y)->diff(u1(x, y), x, x)+diff(u2(x, y), x, y).

I want to define another function as follows

f :=  (y) ->subs(x = 0, g(x, y)) ,

Now, when I want to calculate numerical values for the new function f(0), f(0.1), f(0.2),..... and so on. The following massage appear

Error, (in f) invalid input: diff received 0, which is not valid for its 2nd argument.

What is the problem here.

Amr

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