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 O A
(c)  nilai m jika CD selari dengan AB.   

Penyelesaian:
 
(a)
A B = ( 10 14 ) , O B = ( 4 6 ) C D = ( m 7 ) A B = A O + O B ( 10 14 ) = ( x y ) + ( 4 6 ) ( x y ) = ( 10 14 ) ( 4 6 ) A O = ( 6 8 ) O A = ( 6 8 ) A = ( 6 , 8 )


(b)
| OA |= ( 6 ) 2 + ( 8 ) 2 | OA |= 100 =10 Veckor unit dalam arah  OA = OA | OA | = ( 6 8 ) 10 = 1 10 ( 6 8 ) =( 3 5 4 5 )


(c)
Diberi  CD  selari dengan  AB   CD =k AB ( m 7 )=k( 10 14 ) ( m 7 )=( 10k 14k )

7 = 14k
= ½
m = 10k = 10 (½) = 5

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