Recent content by relyt

Define f: R->R by the rule: f(w) = \left\{ \begin{array}{lr} -5, if x < 0\\ 0, if x=0\\ +5, if x > 0 \end{array} \right. if f onto and/or one-to-one? These questions always get me. Can someone please help me walk through this problem? What do I look for first, etc? those...

Thanks, phreak. Yes, that is how it should read.

Statement: (\exists_{x} \in R) (\forall_{y} \in R) (3x + 2y = 7) Trying to find negation statement. This is what I think it is: (\forall_{x} \in R)(\exists_{y} \in R) (3x + 2y ≠ 7) Is this close?

Now I'm really confused

Hey Hurkyl, I've tried a couple of things, but I know they are not right. Should I post them here anyway :(

Find a counterexample to the statement "For all real numbers u and v, (u + v)^2 is not equal to u2 + v2."