Let O be the origin and the position vector of the point P be - i-2 j+3k. If the position vectors of the points A,B and C are -2 i+ j-3k,2 i+4 j-2k…
JEE Main 2023 — Mathematics Vectors & 3D Geometry
2023mcqeasy
Let O be the origin and the position vector of the point P be −i^−2j^+3k. If the position vectors of the points A,B and C are −2i^+j^−3k,2i^+4j^−2k and −4i^+2j^−k respectively, then the projection of the vector OP on a vector perpendicular to the vectors AB and AC is
Official previous-year question
Held on 10 Apr 2023 · Verified 6 Jul 2026.
Options
A
3
B
38
C
37
D
310
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Solution
Given,
O be the origin and the position vector of the point P be −i^−2j^+3k^,
So, OP=−i^−2j^+3k^
Also given the position vectors of the points A,B and C are −2i^+j^−3k^,2i^+4j^−2k^ and −4i^+2j^−k^
Now finding,
AB=4i^+3j^+k^
AC=−2i^+j^+2k^
And AB×AC=∣i^4−2j^31k^12∣
⇒AB×AC=5i^−10j^+10k^
Now finding the Projection of OP on vector perpendicular to \vec{AB}&\vec{AC} we get,
Projection=∣∣AB×AC∣OP⋅(AB×AC)∣
=51+4+45(−i^−2j^+3k^)(i^−2j^+2k^)=3
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