Q.

The shortest distance, between lines L1 and L2, where L1:x–12=y+1–3=z+42 and L2 is the line, passing through the points A(–4, 4, 3), B(–1, 6, 3) and perpendicular to the line x–3–2=y3=z–11, is          [2024]

1 141221  
2 42117  
3 121221  
4 24117  

Ans.

(1)

We have, L1=x–12=y+1–3=z+42

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

L2=x+43=y–42=z–30

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=||–5572–32320|(4+9)2+(0–4)2+(6–0)2|

=|–5(0–4)–5(0–6)+7(4+9)169+16+36|=|20+30+91221|=141221.