Items tagged with function function Tagged Items Feed

Hi there, 

I'm trying to find a way to find the Preimage for a single point (or a small set) of a complex rational function. I've tried with the command RationalMapPreimage, which sounds like the thing to try, but I can't get my head around how this command works?

(For context, I'm trying to find the preimages of a the fixed/critical/postcritial points of a function something like f(z)=(z2-1)/(z2+1))

Many Thanks

Dear all;

 

Hello everybody, I need your help to dispaly some values obtained using my function f. When I run the code there is no results obtained. Many thanks.

restart:

# The vectors e(i) satify the folowing conditions
e(0)*e(1)=e(n-1) assuming  1<n;
e(0)*e(0)=e(2):
e(1)*e(1)=e(n-1) assuming  1<n: :
e(2)*e(1)=e(n) assuming  1<n:
#
for i from 1  to n-1 do
e(i)*e(0)=e(i+1);
end do:

# We define the function f
f:=e(0)->e(0)+(n-3)*e(1);
f:=e(1)->(n-2)*e(1);
for i from 2  to 3 do
f:=e(i)->(n+i-3)*e(i)+(i-1)*(n-3)*e(n-3+i);
end do:

for i from 4 to n do
f:=e(i)->(n+i-3)*e(i)
end do:

# We define the two vectors
x:=sum(alpha(k)*e(k),k=0..n);
y:=sum(beta(k)*e(k),k=0..n);

#Question : I would like to compute the following  but there is no display of the solution. 
(x*y);
f(x*y);
f(x);
f(y);
x*f(y);
f(x)*y;
f(x*y)- f(x)*y-x*f(y);

Hello,

I have a vector with 4 components. Each component is a polynom.

N := Vector[row](4, {(1) = -(1/2)*t^3+t^2-(1/2)*t, (2) = (3/2)*t^3-(5/2)*t^2+1, (3) = -(3/2)*t^3+2*t^2+(1/2)*t, (4) = (1/2)*t^3-(1/2)*t^2});
N[1]+N[2]+N[3]+N[4];
sum(N[i], i = 1..4);

I don't why the function sum doesn't work in this case. If i do the sum like this N[1]+N[2]+N[3]+N[4];, it works but it doesn't work with the use of the sum function.

Thank you for your help.

 a new function from an existing function and how?

I try to assign a value "y" function "g" but not working. Should be g(0.5,y)=800, but it is not appear in screen. Regards.

value_function.mw

``

restart

``

``

``

g(.5, y) := 200*y;

200*y

(1)

y := 4;

4

(2)

g(.5, y)

g(.5, 4)

(3)

``

``



Download value_function.mw

 

hi. i am tottaly new to the maple and i have a problem.

consider function f with variables x & y which are not independent. x & y are functions of t and the relation is unknown.

for example i wanna to the below job:

define f as f=x^2+y^2

differentiate it with respect to t : diff(f,t) which should give me 2(dx/dt)x+2(dy/dt)y

i've googled it alot and i couldn't find anything usefull.

(the problem is how to set x as a function of t with unknown relation and use it in another function and then differentiate it with respect to t)

thanks alot :)

 

Hello,

I've tried to find the solution to my problem, but none of my attempts was succesful.

I have a function which is one-to-one in a particular domain which I am interested in. I would like to get the inverse function of it only in this domain. Here is my function and plot for xp=0..10000:

x := xp-> (-1)*720.5668720*sinh(0.2043018094e-3*xp-0.8532729286)+84952.59423+4.014460003*10^5*arcsinh(0.1219272144e-1*sinh(0.2043018094e-3*xp-0.8532729286)-0.2032498888)

I would appreciate any help,

Iza

Hello

I want to plot in semilog graph the attached function.where b from 1 to 5 and R from 1 to 100000(in logR)I tried with the plot builder but i think i am doing smthing wrong

``

 

R = 2*b*(b^2-9*b-6)/(10*b^3+21*b^2+16*b+4)

(1)

;

 

 

 

;

;

 

 

Download re.mw

How to realize the Cantor staircase function in Maple? Mathematica has it.

I'd like to stress the three desired properties:

(i) The virtual Cantor function can be evaluated to arbitrary numerical precision.

(ii) For certain arguments, this function automatically evaluates to exact values.

(iii) Mathematical function, suitable for both symbolic and numeric manipulation.

I want to obtain the taylor series of a function say sin(x) at x=0 up to infinity. I mean that I don't want a trauncated series. I tried using "series" and "taylor" but they just give the truncated series.

Hello,

I am trying to write 

D= d/dx + y1*d/dy + y*y1/x*d/dy1 

So that I can apply D to some function L(x,y)

But I don't know how to write the derivative like this without them operation on a function. Can somebody help me? 

Thank you

 

So I am trying to apply the Optimization function to a rather complicated problem I am currently working on, and having some trouble getting maple to cooporate. This is the part of the code that is giving me the error, with error included. All of the variables imputtet when calling OptimizeSpring are constants. If there is any other details I should add, please say so and I will add them promptly :) Thanks alot!
Maple problem

I suspect that it might be related to this suggestion, but I am not sure how to apply it http://www.mapleprimes.com/posts/95113-Optimization-Workaround-For-Operator-Form

Hello, 

I am trying to get W(x,y,y')=y*y'/x

I am trying 

omega:=(x, y(x), (diff(y(x),x)))-> (y(x)*(diff(y(x), x))/x);

but get 

Error, invalid parameter; functional operators require their parameters to be of type symbol or (symbol::type)

 

Can anyone help me out?

 

thank you

Hello,

I use a map() command to get the values of function for each element of vector. Here is an example of a simple task:

restart:

A:=[1,2,8];

f1:=x->2*x;
f1_table_A:=Vector([map(f1,A)]);

I would like to do the same with piecewise function but it doesn't work. Here is an example:

restart:
with(plots):
f:=2*x:
g:=x^2:

h:=x->piecewise( 0<=x and x<= 5, f, 5<x and x <= 10, g ) ;
A:=[1,2,8]:
h_table_A:=map(h,A):

Is it possible to work with piecewise function? Maybe someone has an idea how to do it in different way?

Kind regards,

Iza

Perhaps the question is trivial, but I could not find the solution.

I am solving numerically an ODE (e.g., a simple harmonic oscillator) with the righthand side that contains a random part. For example it is

eq:=diff(a(t),t,t) + a(t) = (1+0.01*R(t))*cos(5*t);

where R(t) is a random function of t. How can I make such a function?

The naive attempt: 

eq:=diff(a(t),t,t) + a(t) = 3.*(1+0.1*rand()/1000000000000.)*cos(5.*t);


gave me a fixed (while random) value, e.g.

...

But, I need this coefficeint to be random each time step.

Any suggestions are very welcome!

 

 

 

1 2 3 4 5 6 7 Last Page 2 of 27