The angle between lines represented by ( ^2 ) y^2-2 x y ( ^2 )+ ( ^2 -1 ) x^2=0 is

Step-by-step solution

Pair of straight lines ( ^2 ) y^2-2 x y ^2 + ( ^2 -1 ) x^2=0 Standard form aligned & a x^2+2 h x y+b y^2=0 & array l a= ^2 -1 h=- ^2 b= ^2 array & = | 2 h^2-a b a+b | aligned gathered = | 2 ^4 - ( ^2 -1 ) ^2 ^2 -1+ ^2 | ^2 + ^2 =1 = | 2 ^4 + ^4 0 | = =90^ gathered