A binary form which has a square factor has its discriminant equal to zero.
This implies the vanishing of the discriminant of the original form.
1 X discriminant of f = ao X disct.
This follows at once from the fact that the discriminant is Mara s) 2 II(/3, -fis)2{II(ar-/3$)}2.
To express the function aoa2 - _ which is the discriminant of the binary quadratic aoxi -+-2a1x2x2-+a2x2 = ai =1, 1, in a symbolic form we have 2(aoa 2 -ai) =aoa2 +aGa2 -2 a1 � al = a;b4 -}-alb?
