Can someone help me with #2? http://www.colvir.net/prof/frederick.tr ... oirNYC.pdf Basically, it says: a) Show that EF // to AB and DC b) Show that ||EF|| = [ ... ] Thanks a lot!
For the second one, EF = ED + DC + CF EF = EA + AB + BF 2EF = ED + EA + DC + AB + CF + BF ED + EA = 0 (couple vectors) CF + BF = 0 (same) EF = (1/2)(DC + AB) icbf to do the first one. It's been a while since geometry :<