Hello fellow members. I recently got a new laptop, and installed Maple of course. Everything went smoothly until I attempted to approximate an answer.

I got the error message:

"[5] Error, invalid input: expected evalf[] index to be of type posint but received %ARG1"

Approximation works perfectly on my other computer and old laptop.

Any help?

I need to apply the midpoint method to an initial value problem. Heres my code:

>mp := proc (f, a, b, N)
local x, k1, k2, y, i, h;
y := array(0 .. N); k1 := array(0 .. N); k2 := array(0 .. N); x := array(0 .. N);
h := evalf(b-a)/N;
x[0] := 0; y[0] := .85;

k1[0] := h*f(0, .85);

k2[0] := h*f(0, .85+.5*k1[0]);

from i = 1 to N do

x[i] := x[i-1]+h;

k1[i] := h*f(0, y[i]);

k2[i] := h*f(0, y[i]+.5*k1[i]);
y[i] := y[i-1]+k2[i-1];
print(x[i], y[i]) end do
end proc

>f := (x,y)-> 1.3/(1+y^2);

>mp(f,0,1,10);

But i get an error message saying "Error, (in mp) initial value in for loop must be numeric or character"

Hello friends;

I want to solve 3 - second orger equations with  6 unkowns. 

When i say just dsolve without boundry conditions it is solving but so complicated. 

_C6Ci  it is giving like that which i dont know the meaning of Ci.

But with boundry conditions it is not solving .

May you help me please where i am doing wrong. I downloaded the file.

Thanks.

Curvedbeam_static_variablethickness_analitik4.mw

Dear All，

I solve an equation  as follows,

m:=dsolve({T(0) = 300, diff(T(t), t) = (min(G1, G2)-Loss)*(1/35513)}, T(t), numeric)

G1,G2, and Loss are functions of T and G1 and Loss are tangent at point A where T=600, when I　want to plot the dsolve solution by odeplot,like this

odeplot(m, [t, T(t)], 0 .. 800)]

I got a curve whose maximum value  is  600( equal to the tangent value) and actually the value should increase after passing the tangent point, Who can tell me where is the problem. Thanks.

Hello everybody!

My name is Mathew and I am a new member of this forum, and this is my first post, so please be lenient towards me:) I wanted to ask for help since my adventure with Maple 18 was supposed to start yesterday, unfortunately I encountered a problem I couldn't solve myself so far- my Maple 18 does not integrate. At all. It has no problem with differentiating, adding, subtracting and such, unfortunately any type of integral is unsolvable by Maple. I tried typing the easiest functions, such as e^2xdx under the integral, unfortunately it is met with following message:

Error, (in int) wrong number (or type) of arguments: invalid option value passed to indefinite integration: {}.

I understood from several tutorials on the internet that this program should not have any problems with dealing with such form of formulas. What could be wrong? How to make  it work as it is supposed to?

Please help me. As I mentioned in the beginning, I am a new member, so in case I did something wrong or placed this post in wrong category- please forgive me;)

The algorithm that I need to replicate is as follows:

real function f(x,y)

integer n; real a,b,c,x,y

f<-max(|x|,|y|)

a<-min(|x|,|y|)

for n=1 to 3 do

b<-(a/f)^2

c<-b/(4+b)

f<-f+2*c*f

a<-ca

end for

end function f

How can I define f,a as  functions that I am later using as variables(in f=f+2cf,b=(a/f)^2)? also, is n just a variable for iteration? 

I've got a function f(x_n) = (x_n-1)^3

and need to show that for the iterative method

x_(n+1)= x_n - f(x_n)/(sqrt(f'(x_n)^2-f(x_n)*f''(x_n), at a simple root we have cubic convergence while at a multiple root, it converges linearly.

I understand that the approach is to write either a recursive function or a sequence, but i'm confused about the structure since both x and n are being incremented

I need to show what happens to the zero r=20 of f(x)= (x-1)(x-2)..(x-20)-(1/10^8)*(x^19) and the hint given is that the secant method in double precision gives an approximate in [20,21].

At present, I'm calling the secant method on f with a tolerance of 1/(10^12) with an initial x=20, but I'm stuck as to what the second initial value would be. What is the right approach to this question?

I've plotted the graph for this max function. Is there any way I can find the points of discontinuity in general and then use that to compute the derivatives at points where it exists?

I'm trying to get the RHL of exp1:=(2/(1+e^(-1/x)) as x->0+

and have l2:=limit(exp1,x=0,right) but that isn't giving me a value. How do I correct this? 

I have several plots and I'm using the display procedure,

display(seq(p1[i], i = 1..3), pts1, pts2);

to draw them. I want them to be displayed in the specified order, i.e., pts1 and pts2 should be in the foreground. Unfortunately, the display procedure ignores the order. How to enforce the specified order?

I am facing a kind of strange problem. Whenever I enter Int(exp(-s t) t^2,t) and try to see full solution using Student[Calculus1]:-ShowSolution(), it gives empty square brackets [ ] as superscripts of e. If I restart Maple engine and perform the same, sometimes it produces right solution. Kindly help, what is this? Same integral does not give problem if done with parameter 'r' instead of 's'.

Heun functions arise in the solutions of various differential equations, for instance for the Schroedinger equation for the hydrogen atom in physics, which is also of chemical interest.  Although they have been nominally included in Maple for several years, they are still in a primitive state; despite their obscurity and intractable nature, there seems not to exist much possibility, within Maple, to convert these functions into better known and characterised functions.  A similar condition holds for Lame and spheroidal functions that are invaluable in the solution of differential equations in physics but are not even mentioned in Maple. 

The compilation of mathematical functions by Abramowitz and Stegun was published half a century ago, but there are still important functions explained therein that are lacking from Maple, not to mention the successor in the NIST Digital Library of Mathematical Functions.

Integral equations are another weak component of Maple; the present content relies on a basis of work of ProfessorCorless and his student submitted to the 'Maple Share Library' -- decades ago.  Forty years ago, David Stoutemyer generated some procedures to solve non-linear integral equations in Reduce, but forty years later Maple has no benefit from that knowledge.

We can only hope that Maple 19 will remedy some of these gross deficiencies.  The teaching, learning and practice of physics will benefit from their implementation.

At the internet site of The Heun Project, a strong declaration is made that only Maple incorporates Heun functions, which arise in the solution of differential equations that are extremely important in physics, such as the solution of Schroedinger's equation for the hydrogen atom.  Indeed solutions appear in Heun functions, which are highly obscure and complicated to use because of their five or six arguments, but when one tries to convert them to another function, nothing seems to work.  For instance, if one inquires of FunctionAdvisor(display, HeunG), the resulting list contains

"The location of the "branch cuts" for HeunG are [sic, is] unknown ..." followed by several other "unknown" and an "unable". Such a solution of a differential equation is hollow.

Incidentally, Maple's treatment of integral equations is very weak -- only linear equations with simple solutions, although procedures by David Stoutemyer from 40 years ago are available to enhance this capability.

When can we expect these aspects of Maple to work properly, for applications in physics?

hi, is there a way to collect all commands in one place which have been used during a clickable math session of a document? in fact this would help in creating automated tasks.