How to caculate imaginary matrix in Matlab?

[yorande]

imaginary matrix

I enter the matrix with i to denote the imaginary part.
But it seems that Matlab has ttaken it as a symbol.
Ohter symbols were defined.
And I read in a book that i is predefined for the imaginary parts.
Why can't it work in matrix?
And when I caculate a linear matrix, some of the variation answers even have "conj" part??
How could it be that?
Thanks!!!

 

[echo47]

example to calculate imaginary by matlab

Here's a 2x2 matrix of complex numbers:
a = [3+5i 4-7i; -2+3i -5-i];

What's that about a linear matrix and conj? Can you show us an example?

 

[a_ronagh]

Hi
Be careful yorande.If you use the '*' sign between i and other variables,it will consider it as a variable if you have asigned it some value before.
So check whther you have not defined it as a variable before and also use it as echo14 has showed.I hope your problem cab be solved.

 

[zorro]

Remember that “j” can be used in place if “i” (as it it usual in engineering).
It is not a good idea to use “i” or “j” as variable names.
Regards

Z

 

[yogesh28970837]

Be careful while using variable names i and j in matlab, because by at start they r initialized as sqrt(-1) so to declare imaginary variable just write - 1+2*i.

u van declare matrix of imag nos in similar manner to that of real nos and perform simple mathematical operations such as add,substract,division .

Also u can use inbuilt funs such as conj for imaginary nos and to convert into polar form u can get angle and magnitude directly.

 

[yorande]

Thanks to you all!

I'm trying to caculate a matrix with something like:
[1/r1 c1*f*i 0 0 1;
0 0 g2*i 1 1]

You see, there are many symbols except numbers.
and the r1 c1 and g2 are not variables.
The problem is now the matlab just take i as a sybol as c1 too.

I have defined the r1 c1 and g2, but not i.
I thought it should take it as the imaginary part. but it did not.

And things like c1*fi or (c1*f)i did not work either.

by the way, conj means i too??
could i use conj to define the imaginary part?

 

[main_road]

conj is the conjugate of a complex number. For example, conj(4-5i)=4+5i.

I don't have your problem. Just to convince you. Here are the results of a series of executions:

>> r1=5; c1=4.2; f=7.5;g2=3

g2 =

3

>> A=[1/r1 c1*f*i 0 0 1; 0 0 g2*i 1 1]

A =

0.2000 0 +31.5000i 0 0 1.0000
0 0 0 + 3.0000i 1.0000 1.0000

 

[alizadeh_m]

most common operations on a real matrix have a slightly different form for the complex matrix. like At[i,j] = conj(A[j,i]) for a complex matrix. and MATLAB will calculate this form.

 

[hamidr_karami]

hi
this is an example for you
s=[1 2 3+i;1-2j 1 2;1 2 3]

s =

1.0000 2.0000 3.0000 + 1.0000i
1.0000 - 2.0000i 1.0000 2.0000
1.0000 2.0000 3.0000
>> inv(s)

ans =

-0.2353 + 0.0588i 0.1176 + 0.4706i 0.1765 - 0.2941i
0.1176 + 1.4706i -0.0588 - 0.2353i 0.4118 - 1.3529i
0 - 1.0000i 0 0 + 1.0000i
i hope that you interested
bye