AP EAMCET2014MathematicsPair of Lines
If x^2+ y^2+2 y=a^2 represents a pair of perpendicular lines, then equals to
Options
- A4 a
- Ba
- C2a
- D3a
Correct answer
B. a
Step-by-step solution
Let given line be x^2+ y^2+2 y-a^2=0 Here, a=1, b= , h=0, g=0, f= , c=-a^2 Condition for perpendicular line a+b=0 1+ =0 =-1 Condition of pair of lines array ccc & a b c+2 f g h-a f^2-b g^2-c h^2=0 & 1 (-a^2 )+0-1( )^2-0- (-a^2 )(0)=0 & -a^2 - ^2=0 & ^2=- a^2 & ^2=-(-1) a^2 ( =-1) & ^2=a^2 =a array