Jawabanmu

2014-06-23T14:59:24+07:00
|A| = 10          ; |B| = 6          ; α = π/3
|A-B|  = ........?
|A-B|² = |A|² -2|A||B|cos α + |B|²
|A-B|² = (10)² - 2(10)(6)cos π/3 + (6)²
          = 100 - 120 (1/2) + 36
          = 100 - 60 + 36
|A-B|² = 76
|A-B|  =  √76
          = √4.√19
|A-B|  = 2√19