let give F(x) = (1/(x^2 +1)) prove that ∃ P_n ∈ Z_n [x] /
F^((n)) (x)= ((P_n (x))/((1+x^2 )^n )) find a relation of recurence between
the P_n .prove that all roots of P_n are reals and smples.
If one line of the equation :
ax^3 +bx^2 y+cxy^2 +dy^3 =0
bisects the angle between the
the other two then prove
(3a+c)^2 (bc+2cd−3ad)=
(b+3d)^2 (bc+2ab−3ad) .