If a line OP makes angles θ1,θ2,θ3 with co-ordinate planes XOY,YOZ,ZOX, then sin2θ1+sin2θ2+sin2θ3=
If tan θ1, tan θ2, tan θ3 are the real roots of x3−(a+1)x2+(b−a)x−b=0 where θ1, θ2, θ3 are acute then θ1+θ2+θ3=