Question

if a vector equals î - 3 j cap + 5 k cap and b vector equal to 2î - alpha j cap - k cap C vector equals to 2î + j cap - 2 k cap are coplanar then find the value of alpha​

Answer 1

Answer:

Let,

a⃗ =2i^+2j^−2k^

b⃗ =5i^+yj^+k^

c⃗ =−i^+2j^+2k^

If a⃗ ,b⃗ ,c⃗ are coplanar, then their scalar triple product should be zero.

[a⃗ b⃗ c⃗ ]=0

That implies,

(a⃗ ×b⃗ ).c⃗ =0

By cyclic rotation,

(c⃗ ×a⃗ ).b⃗ =0

We have,

c⃗ ×a⃗ =6j^−6k^

Therefore,

(6j^−6k^).(5i^+yj^+k^)=0

6y−6=0

y=1

Explanation:

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Answer 2

Answer:

here is the answer

Explanation:

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