Let a straight line L pass through the point P(2, -1, 3) and be perpendicular to the lines x-12 = y+11 = z-3-2 and x-31 = y-23 = z+24. If the line L intersects the yz-plane at the point Q, then the distance between the points P and Q is:
- 10
- 2
- 2 3
- 3
Answer
(4) 3
Solution
L both lines ⇒ d= d1 d2=(2,1,-2) (1,3,4)=(10,-10,5) (2,-2,1)
L: (2+2 , -1-2 , 3+ ); on the yz-plane x=0 ⇒ =-1
⇒ Q(0,1,2)
∴ PQ= 4+4+1=3
Answer: (4)