MHT CET20192 May 2019Morning ShiftMathematicsPair of LinesActual
The joint equation of pair of straight lines passing through origin and having slopes 1 + 2 and 1 1 + 2 is ________
Options
- Ax 2 - 2 2 x y + y 2 = 0
- Bx 2 - 2 2 x y - y 2 = 0
- Cx 2 + 2 x y - y 2 = 0
- Dx 2 + 2 x y + y 2 = 0
Correct answer
A. x 2 - 2 2 x y + y 2 = 0
Step-by-step solution
Pair of lines passing through origin is a x 2 + 2 h x y + b y 2 = 0 w h e r e m 1 + m 2 = - 2 h b = 2 + 1 + 2 - 1 = 2 h b = - 2 2 m 1 m 2 = a b = 2 + 1 2 - 1 = 1 Hence, pair of lines is x 2 - 2 2 x y + y 2 = 0