4.7 Vektor, SPM Praktis (Kertas 2)


4.7 Vektor, SPM Praktis (Kertas 2)

Soalan 2:
Diberi AB =( 10 14 ),  OB =( 4 6 ), dan  CD =( m 7 ), carikan
(a)  koordinat A,
(b)  vektor unit dalam arah OA
(c)  nilai m jika CD selari dengan AB.       

Penyelesaian:  
(a)
AB =( 10 14 ),  OB =( 4 6 ) CD =( m 7 ) AB = AO + OB ( 10 14 )=( x y )+( 4 6 ) ( x y )=( 10 14 )( 4 6 ) AO =( 6 8 ) OA =( 6 8 ) A=( 6,8 )

(b)
| OA |= ( 6 ) 2 + ( 8 ) 2 | OA |= 100 =10 the unit vector in the direction of  OA = OA | OA | = ( 6 8 ) 10 = 1 10 ( 6 8 ) =( 3 5 4 5 )

(c)
Given  CD  parallel  AB   CD =k AB ( m 7 )=k( 10 14 ) ( m 7 )=( 10k 14k )
7 = 14k
k = ½
m = 10k = 10 (½) = 5

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