R = 7i + 7j, :: R=7√2
Answers
Answered by
0
Answer:
The required vector r=t(a+b),t is a scalar
⇒r=t[
9
1
(7i−4j−4k)+
3
1
(−2i−j+2k)]
=
9
t
(i−7j+2k)
Since r=3
6
⇒∣r∣
2
=54
⇒
81
t
2
(1+49+4)=54⇒t
2
=81⇒t=±9
Hence, r=±(i−7j+2k)
Answered by
0
Answer:
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Explanation:
Let θ be the angle between the given lines.
The given lines are parallel to the vector.
b
1
=1+2j+2k and
b
2
=3i+2j+6k respectively.
So, the angle θ between them is given by
cosθ=
∣
∣
∣
∣
b
1
∣
∣
∣
∣
∣
∣
∣
∣
b
1
∣
∣
∣
∣
b
1
.
b
2
=
∣i+2j+2k∣∣3i+2j+6k∣
(i+2j+2k)(3i+2j+6k)
=
1+4+4
9+4+36
3+4+12
=
21
19
⇒θ=cos
−1
(
21
19
)
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