# Math Help - Matlab help

1. ## Matlab help

Hey, im new to programing in matlab and am having a really hard time with it so far. Im stuck on this one problem:

Define vector xi=(i-m)/(m+3); i=1,...,(2m-1) using a single loop

could someone help me out here. im not even really sure how to start this.
I know how to do simple loops like
for i=1:1:5
x=x+8
end

but thats as far as my skills go right now.
Any help would be awesome

2. Originally Posted by george
Hey, im new to programing in matlab and am having a really hard time with it so far. Im stuck on this one problem:

Define vector xi=(i-m)/(m+3); i=1,...,(2m-1) using a single loop

could someone help me out here. im not even really sure how to start this.
I know how to do simple loops like
for i=1:1:5
x=x+8
end

but thats as far as my skills go right now.
Any help would be awesome

i posted this in the programing section too, so feel free to delete that one.
With one loop:

Code:
m=10;
xi=zeros(1,2*m-1);

for idx=1:2*m-1;
xi(idx)=(idx-m)/(m-3);
end
With zero loops

Code:
m=10;
xi=([1:2*m-1]-m)/(m-3);
RonL

3. Originally Posted by george
Hey, im new to programing in matlab and am having a really hard time with it so far. Im stuck on this one problem:

Define vector xi=(i-m)/(m+3); i=1,...,(2m-1) using a single loop

could someone help me out here. im not even really sure how to start this.
I know how to do simple loops like
for i=1:1:5
x=x+8
end

but thats as far as my skills go right now.
Any help would be awesome

i posted this in the programing section too, so feel free to delete that one.
I have the following code, which may help you to learn the idea.

Code:
s=100;
k=3;
for n=1:(k+1)
x(n)=1;
end;
for n=(k+1):(s-1)
mn=mod(n,12);
if mn==0
p=-1;
elseif mn<=3
p=0;
else
p=245/1000;
end;
x(n+1)=x(n)-p*x(n-k);
end;
n=1:s
plot(n,x(n),'-rs','LineWidth',1,'MarkerEdgeColor','b','MarkerSize',2)
%n=1:(s-1)
%plot(x(n),x(n+1),'-rs','LineWidth',1,'MarkerEdgeColor','b','MarkerSize',2)
grid on;
It's better you ask stuff like this to http://www.mathhelpforum.com/math-he...uter-software/

4. can someone explain to me what "idx" means?
thanks

never mind. "idx" is just a variable i think
but could some one help me understand what the code is doing?

haha.. never mind. i understand it. Im learning, just very slowly.

5. Originally Posted by george
can someone explain to me what "idx" means?
thanks

never mind. "idx" is just a variable i think
but could some one help me understand what the code is doing?

haha.. never mind. i understand it. Im learning, just very slowly.
idx is the name of the counter that runs from 1 to 2*m-1 1 by 1.

a very helpful website for the questions is MATLAB