Ques. 1JEE Main 2024, 27 January (Evening Shift)
Let the image of the point (1,0,7) in the line x1= y-12= z-23 be the point ( , , ). Then which one of the following points lies on the line passing through ( , , ) and making angles 2 3 and 3 4 with y-axis and z-axis respectively and an acute angle with x-axis ?
- (1,-2,1+ 2 )
- (3,-4,3+2 2 )
- (3,4,3-2 2 )
- (1,2,1- 2 )
Answer
(3) (3,4,3-2 2 )
Solution
Foot M( ,1+2 ,2+3 ); PM ( i+2 j+3 k):
( -1)+2(2 +1)+3(3 -5)=0 14 =14 =1, M(1,3,5)
[figure]
∵ M is the mid-point of PQ: ( , , )=2M-P=(1,6,3)
m= 2 3=- 12, n= 3 4=- 1 2
l2=1- 14- 12= 14
∵ acute angle with x-axis l=+ 12
Point on line: (1+ 2, 6- 2, 3- 2 ); =4 (3,4,3-2 2 )
Answer: (3)