Q.

The shortest distance between the lines x34=y+711=z15 and x53=y96=z+21 is           [2024]

1 179563  
2 185563  
3 187563  
4 178563  

Ans.

(3)

Given lines can be written as

x34=y(7)11=z15 and x53=y96=z(2)1

a1=3i^7j^+k^, a2=5i^+9j^2k^, b1=4i^11j^+5k^

and b2=3i^6j^+k^

  a2a1=2i^+16j^3k^ and b1×b2=|i^j^k^4115361|=19i^+11j^+9k^

Shortest distance between two lines,

d=|(a2a1)·(b1×b2)||(b1×b2)|  d=|38+17627|361+121+81=187563.