matrix
	a = [1, 2, 3; 4, 5, 6]
answer is surrounded by ! symbols
	! 1. 2. 3. !
	! 4. 5. 6. !

sum(a, 'c') adds the terms along each row?
	! 6. !
	!15. !

sum(a, 'r') adds the terms along each column?
	! 5. 7. 9. !

diag(a) the entries along the diagonal
	! 1. !
	! 5. !

rref(a) row reduce
!   1.    0.  - 1. !
!   0.    1.    2. !

subscripts with ( , )
a(2,3)
	yields 6

assign 8
a(2, 3) = 8
!   1.    2.    3. !
!   4.    5.    8. !


colon
1:10 
! 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. !

10:-2:0
! 10. 8. 6. 4. 2. 0. !

a(1:2,3)
gives the 3 column

So does a(:, 3)


conjugate transpose a'

a*a' or a'*a

inverse b^(-1)

b^n power

sqrt(-1) is %i, %pi is pi, %e is e, %inf is oo, %t is true

abs is complex abs value

zeros(3,4)

ones(3,4)

eye(3,3)

rand(3,4)

concatenation a = [1, 2;3, 4]; b=[2, 0;0,2]; augment is [a, b]

plot(x,y)
	x = 0:0.05:2*pi
	y =sin(x)

det(a) determinant

inv(a) inverse

the dot operators .*

not equal is ~= 

spec is spectrum

[v,d]=spec(a)

real(a+b*%i) is `a'

imag(a+b*%i) is `b'

abs(a+b*%i) is sqrt(a^2 + b^2)