Q.

The shortest distance, between lines L1 and L2, where L1:x12=y+13=z+42 and L2 is the line, passing through the points A(–4, 4, 3), B(–1, 6, 3) and perpendicular to the line x32=y3=z11, is          [2024]

1 141221  
2 42117  
3 121221  
4 24117  

Ans.

(1)

We have, L1=x12=y+13=z+42

Equation of the line passing through the points A(–4, 4, 3) and B(–1, 6, 3) is

L2=x+43=y42=z30

Here, a1=2,b1=3,c1=2; x1=1,y1=1,z1=4

a2=3,b2=2,c2=0; x2=4,y2=4,z2=3

  Required shortest distance

d=||557232320|(4+9)2+(04)2+(60)2|

=|5(04)5(06)+7(4+9)169+16+36|=|20+30+91221|=141221.