Question

If P, Q, R and S are the points with
position vectors
i + j - k, 2i - ; +3k, 27 - 3k and
37 - 2j + k respectively, then the angle
between PQ and RS is​

Answer 1

Answer:

ANSWER

∴ directions of

PQ

=(2

i

^

−

i

^

)+(5

j

^

−

j

^

)−

k

^

=(

i

^

+4

j

^

−

k

^

)

∴ directions of

RS

=(

i

^

−3

i

^

)+(−6

j

^

−2

j

^

)+(−

k

^

+5

k

^

)

=(−2

i

^

−8

j

^

+2

k

^

)

∴

i

^

+4

j

^

−

k

^

=

2

−1

(−2

i

^

−8

j

^

+2

k

^

)

∴d(

PQ

)=

2

−1

(d(

RS

))

Hence line PQ and Rs are parallel.