More help...

e = belongs to
v. = vector

If k >= 2 and v.x e R^k, prove that there exists v.y e R^k such that v.y =/= v.0 but v.x*v.y = 0.

All I know is that R^k is a set of all ordered k-tuples (? don't know what that means really..) and that x*y = the sum^k of xi*yi, i=1. But that's about it.. my professor doesn't really teach...

yup, more help please...

- Nicole