
Matrices
Let K be a finite field with only the two elements 0 and 1, where 1+1=0.
(i) How many 2 x 2 matrices with entries in K are there?
Ok so for this I expect the answer to be the number of different ways one can write a 4 digit combination of the numbers 1 and 0 and so my answer is 16. But it just seems so trivial...does it seem right?
(ii) How many of these are nonsingular?
Now for this I know that a matrix is nonsingular if it is invertible, which is the case when the determinant of the matrix is not equal to 0. But the thing is, I got quite confused about the part where 1+1=0. How do I factor this in?