Jul 30, 2009 #1 jian1 Messages 8 Reaction score 0 never mind, I figured it out. :) thanx Last edited: Jul 31, 2009
Jul 30, 2009 #2 Dick Science Advisor Homework Helper Messages 26,254 Reaction score 623 Maybe you should show an attempt. |f1+f2|<=|f1|+|f2|.