The sum of all values of α, for which the points whose position vectors are i-2 j+3 k,2 i-3 j+4 k,(α +1) i+2 k and 9 i+(α -8) j+6 k are coplanar, is…
JEE Main 2023 — Mathematics Vectors & 3D Geometry
2023mcqeasy
The sum of all values of α, for which the points whose position vectors are i^−2j^+3k^,2i^−3j^+4k^,(α+1)i^+2k^ and 9i^+(α−8)j^+6k^ are coplanar, is equal to
Official previous-year question
Held on 6 Apr 2023 · Verified 6 Jul 2026.
Options
A
−2
B
2
C
6
D
4
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Solution
Let the given vectors be A=i^−2j^+3k^,B=2i^−3j^+4k^,C=(α+1)i^+2k^andD=9i^+(α−8)j^+6k^
We know that if the vectors are coplanar then [ABACAD]=0