First Matlab Matrix operations

>>a = 1:4
   a =  1     2     3     4

>> 2*a
  ans =
     2     4     6     8

>> 2 / a
  ??? Error using ==> /
  Matrix dimensions must agree.

>> 2 ./a
  ans =
    2.0000    1.0000    0.6667    0.5000

>> a .*a
  ans =
     1     4     9    16

>> a .^(.5)
  ans =
    1.0000    1.4142    1.7321    2.0000

>> b = a'
   b =
     1
     2
     3
     4

>> a*b
   ans =  30

>> b*a
   ans =
     1     2     3     4
     2     4     6     8
     3     6     9    12
     4     8    12    16

>> c=b*a
   c =
     1     2     3     4
     2     4     6     8
     3     6     9    12
     4     8    12    16

>> x=1:9
  x =
     1     2     3     4     5     6     7     8     9

>> y = reshape(x,3,3)
  y =
     1     4     7
     2     5     8
     3     6     9

>> inv(y)
 Warning: Matrix is singular to working precision.
 ans =
   Inf   Inf   Inf
   Inf   Inf   Inf
   Inf   Inf   Inf

>> y(3)=0
  y =
     1     4     7
     2     5     8
     0     6     9

>> inv(y)
  ans =
   -0.3333    0.6667   -0.3333
   -2.0000    1.0000    0.6667
    1.3333   -0.6667   -0.3333

>>