Question

F(x)=ax3+bx2+cx+d is biquadric or not

Answer 1

Explanation:

If a,b,c,dεRandf(x)=ax3+bx2−cx+da,b,c,dεRandf(x)=ax3+bx2-cx+d has local extrema at two points of opposite signs and ab>0ab>0 then roots of equation ax2+bx+c=0ax2+bx+c=0 (A) are necessarily negative (B) have necessarily negative real parts (C) have necessarily positive real parts (D) are necessarily positive