Q.
If position vectors of points P,Q,R with respect to origin O are r1→=3i^−2j^−k^,r2→=i^+3j^+4k^ and r3→=2i^+j^−2k^ , then the distance between P and plane OQR is:-
Here, coordinates of P(3,−2,−1),Q(1,3,4),R(2,1,−2) .
Equation of plane using three point form i.e. ∣∣x−01−02−0y−03−01−0z−04−0−2−0∣∣=0
i.e. 2x−2y+z=0 .
Now, distance of P from this plane =22+(−2)2+12∣2(3)−2(−2)+(−1)∣=3 units