The angle between the pair of lines x2−2xysecα+y2=0 is

If θ is acute angle between pair of lines represented by the equation ax2+2hxy+by2=0then  cosθ=a+b(a−b)2+(2h)2For the equation x2−2xysecα+y2=0,a=1,2h=−2secα,b=1   Hence, cosθ=20+4sec2α=22secα=cosαTherefore, θ=α