MA 2071 Abstract Vector Spaces

For each set below, decide if it is a vector space or not. Assume the following notation:

M22 = set of all 2x2 matrices

P2 = set of all 2nd degree polynomials

Note: you must either prove that it is a vector space using the definition or come up with a counterexample to disprove it

1. The set of matrices where a12 = - a21 in M22

2. The set of all upper triangular matrices in M33

3. { x2 + bx + c } in P2

4. { all "even" functions; f(x) = f(-x) }

5. { all solutions to d2y/dx2 + y = 0 }

6. {all f(x) such that integral a to b of f(x)dx = 0 } (a and b fixed )

7. {all nonsingular (invertible) 3x3 matrices }

8. { matrices with 0 on the diagonal } in M22

9. { all f(x) where f(0) = 1 }

10. { ax2 + bx + c where a = 2b} in P2

11. In problems 1,2 and 7 can you find a) a basis ? b) tell what the dimension is?