Command Line statements for a matrix

I'm having trouble setting up this code.

My goal is to set up a 3x3 Matrix A. Then write command line statements to perform the following operations.

a) Interchange columns 2 and 3

b) add a fourth column of zeros

c) insert a row of 1's as the new second row. ( move current 2nd and 3rd rows down)

d) remove the second column

Any help would be greatly appreciated, Thanks

[per isakson]

Isn't this your homework?

[Joseph]

It is hw But we are allowed to use the Matlab Forum for help as long as it is cited.

[Joseph]

I have b) and d) completed. the other 2 are giving me problems. thanks

Answer 1

[per isakson]

Ok, here is one way of doing a)

    >> m = magic( 3 )
    m =
         8     1     6
         3     5     7
         4     9     2
    >> m( :, [1,3,2] )
    ans =
         8     6     1
         3     7     5
         4     2     9
    >>

Why don't you try to do it with the function, cat( 2, m(:,1), ... )

.

Continue:

Does "command line statements" say that each task shall be done with one function call? If two are allowed

    >> m1 = m( [1,1,2,3], : )
    m1 =
         8     1     6
         8     1     6
         3     5     7
         4     9     2
    >> m1(2,:) = 1
    m1 =
         8     1     6
         1     1     1
         3     5     7
         4     9     2

otherwise

    >> cat( 1, m(1,:), ones(size(m(1,:))), m([2,3],:) )
    ans =
         8     1     6
         1     1     1
         3     5     7
         4     9     2

[Joseph]

That helps a lot. Now for c), I have no problem replacing a row with 1's, but inserting and moving other rows down is giving me peroblems