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1. given that the point a has a position vector 3i-7j the point b has a position vector 8i+3j
Find the vector AB
i GOT 5I-10J
then find the magnitude of ab
Which i got to be 5 root 5

The answer said a is 5i+10j can anyone explain
2. Draw a diagram and make it as simple as possible
The 5i comes from 8-3, as you’re starting from A not 0, the J comes from +7j+3j, you’re answer to part B should be the same cause you’re squaring a negative so it becomes positive anyway
3. (Original post by toton)
given that the point a has a position vector 3i-7j the point b has a position vector 8i+3j
Find the vector AB
i GOT 5I-10J
then find the magnitude of ab
Which i got to be 5 root 5

The answer said a is 5i+10j can anyone explain
(8i+3j) - (3i-7j)

= (8-3)i + (3-(-7))j

= 5i+10j

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Updated: March 18, 2018
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