If the position vectors off A,B,C and D are `2hati+hatj,hati-3hatj,3hati+2hatj and hati+lamdahatj`, respectively and `AB||CD`, then `lamda` will be

A. `-7`

B. 7

C. `-6`

D. None of these

A. `-7`

B. 7

C. `-6`

D. None of these

Correct Answer – C

Now, `PQ= (hati – 3 hatj)-(2 hati + hatj) = – hati-4hatj`

`and RS= – 2hati + (mu – 2)hatj`

Given, `PQ||RS rArr PQ= lambda RS`

`-hati – 4 hatj =[ lambda { – 2hati +(mu-2)hatj}]`

`rArr lambda = 1//2 and mu = -6 `