Jawapan

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  • Pengguna Brainly
2016-04-22T16:58:07+08:00
Question 1: THIS IS THE SAME METHOD..
Given that O (0, 0), A (3, 4) and B (–9, 12), find in terms of the unit vectors,   and  j˜.
(a) AB(b) the unit vector in the direction of AB 

Solution:
(a)
A=(−3,4), thus OA=−3+4B=(−9,12), thus OB=−9+12AB=AO+OBAB=−(−3+4)+(−9+12)AB=3−4−9+12AB=−6+8
(b)
The magnitude of |AB|,|AB|=(−6)2+(8)2=10∴The unit vector in the direction of AB,AB|AB|=110(−6+8)=−35+45
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