IIT JEE 2008 question

is it d?

wait i ll post my solution

ha....

this un can b dun by finding the d-ratios of l1,l2,l3 wich are perpendicular to p1p2 , p2p3 , p1p3

line L₃ is the intersection of P₁and P₂ , then direction cosine of L₃ is = 2(j+k) ( by solving the dterminant)

L₁ is the intersection of planes P₃and P₂ then direction cosine of L₁ is = -4(j+k)

line L₂ is intersection of P₁and p₃ then the direction cosine of L₂ is=-2(j+k)

family of planes passing through P₁ and P₂ is P₁+λP₂=0

then x(1+λ)+(λ-1)y+z(1-λ)+(λ-1)=0

there is no value of λ which satisfies the aboce equation , hence option d

Simple!!...D.cosiness of these lines r propotional to (0,1,1)...if u notice....