Manipal MET2018MathematicsStraight Lines
The product of the perpendicular from (-1,2) to the pair of lines 2 x^2-5 x y+2 y^2+3 x-3 y+1=0 is
Options
- A5 12
- B12 5
- C6 5
- D5 6
Correct answer
B. 12 5
Step-by-step solution
array lr (b) 2 x^2-5 x y+2 y^2+3 x-3 y+1=0 & (x-2 y+1)(2 x-y+1)=0 array Two equations are x-2 y+1=0 and 2 x-y+1=0 . Length of perpendiculars from (-1,2) are aligned & p₁= | -1-4+1 1+4 |= 4 5 and p₂= | -2-2+1 5 |= 3 5 & Product =p₁ p₂= 12 5 aligned