Tentukan:
a +2 c –3 b
|a+b|
a.c
Diketahui a = -5i +5j +7k , b = -3i +4j +7k dan c = -4i +2j +7k.
Penjelasan dengan langkah-langkah:
a = -5i +5j +7k = (-5,5,7)
b = -3i +4j +7k = (-3,4,7)
c = -4i +2j +7k = (-4,2,7)
•a+2c-3b
= (-5,5,7) + 2 (-4,2,7) – 3 (-3,4,7)
= (-5,5,7) + (-8,4,14) – (-9,12,21)
= (-4,-3,0)
• |a+b|
cari a+b dulu
= (-5,5,7) + (-3,4,7) = (-8,9,14)
cari |a+b|
= √(-8)²+9²+14² = √64+81+196 = √341
•a.c
= (-5,5,7) (-4,2,7) = 20+10+49 = 79