Diketahui a = -5i +5j +7k , b = -3i +4j +7k dan c = -4i +2j +7k.

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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