1. The problem statement, all variables and given/known data a. Is it possible to have u ↓ v undefined? b. Is it possible to have u ↓ v = v ↓ u ? c. Explain why u ↓( v ↓ w ) = u ↓ w . 2. Relevant equations 3. The attempt at a solution I know a is possible if the length of vector v is 0. I think be is false, but not sure. And c, Im not sure. I'm really just unsure how to demonstrate a, b, and c mathematically, and the question implies I use diagrams to demonstrate my answers. Any advice or assistance is appreciated..