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22nd June 2008, 16:27 #1
matlab define matrix
How to define a matrix of variables in matlab?
For example I want a matrix like:
a=[sin(t) cos(t);cos(t) sin(t)]
so that "t" be a variable, when I assign t=.5 it should give to me
[0.4796 0.8776;0.8776 0.4796]
how should I do that?
help me if u can! thanks!

22nd June 2008, 16:39 #2
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matlab matrix variables
I don't quite understand your question. If I simply type your two statements into MATLAB:
t = .5
a = [sin(t) cos(t);cos(t) sin(t)]
it displays the resulting matrix as you requested:
0.479425538604203 0.877582561890373
0.877582561890373 0.479425538604203
Or do you want it formatted with square brackets and semicolon?

22nd June 2008, 16:39

22nd June 2008, 17:21 #3
matlab matrix with variables
No,
you should type the matrix definition first
I want to define a matrix (containing a variable such as "t")
then put it in a loop, and change the variable, and get different values

you should type: ( as I did! )
>> syms t
>> a=[sin(t) cos(t);cos(t) sin(t)]
a =
[ sin(t), cos(t)]
[ cos(t), sin(t)]
>> t=1.2;
>> a
a =
[ sin(t), cos(t)]
[ cos(t), sin(t)]

is it clear?! I want "t" in the matrix to be a variable!
How can I do that?
thanks!

22nd June 2008, 17:21

22nd June 2008, 18:31 #4
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matlab variable matrix
Oh, that looks like Maple symbolic processing. Sorry, I've never explored that aspect of MATLAB.

22nd June 2008, 18:31

19th July 2008, 14:24 #5
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define variable in matlab
Code:syms t a=[sin(t) cos(t);cos(t) sin(t)] a=subs(a,t,0.1)
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3rd June 2011, 08:50 #6
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Re: matlab define matrix
Hi ,
Is there any way to write a for loop in MATLAB to read the files i.e. texts that
are saved in a folder and do some operation on each in every iteration. So
let say if I have files 1.txt, 2.txt,,... all saved in a folder called
LOSS. i want to open 1.txt first> do some calculation and display the
result, then open 2.txt and do the same calculation, then 3.txt and so on.
thanks
Anvari

11th July 2012, 10:06 #7
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Re: matlab define matrix
a=[0.5 0 0 0 ;1 1 0 0;0 1 3 0;0 0 1 10];
k1=char;
k2=char;
k3=char;
k4=char;
s=char;
c=[k1 k2 k3 k4];
b=[4.5;1;0;0];
i=eye(4);
q=b*c;
t=s*i;
w=tq;
e=det(w);
%++++++++++++++++++++++++++++++why this not true?

15th July 2013, 02:39 #8
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15th July 2013, 02:52 #9
Re: define variable in matlab
1 members found this post helpful.

15th July 2013, 02:52

15th July 2013, 23:31 #10
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Re: define variable in matlab
Is there a way in which I can resolve this.........?
Thanks for the help.

16th July 2013, 05:53 #11
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