Let the point, on the line passing through the points P(1,-2,3) and Q(5,-4,7), farther from the origin and at a distance of 9 units from the point P, be ( , , ). Then 2+ 2+ 2 is equal to :
- 150
- 155
- 160
- 165
Answer
(2) 155
Solution
PQ=(4, -2, 4), | PQ|=6 unit vector 13(2, -1, 2)
Points at distance 9 from P: (1, -2, 3) 9 13(2, -1, 2)
=(1, -2, 3) (6, -3, 6)
(7, -5, 9) or (-5, 1, -3)
Squared distances from O: 49+25+81=155 and 25+1+9=35
farther point (7, -5, 9) 2+ 2+ 2=155
Answer: (2)