1) If f(x) = x3+bx2+cx+d and 0<b2<c, then in (-∞, ∞) A) f(x) is a strictly increasing function B) f(x) has local maxima C) f(x) is a strictly decreasing function D) f(x) is bounded Answer: Option AExplanation:f(x) = x3+bx2+cx+d and 0<b2<c .'. f'(x) = 3x2+2bx+c Discriminant = 4b2 -12c = 4(b2 - 3c)<0 f'(x) >0 ∀ xΕ R Thus,f(x) is strictly increasing ∀ x Ε R
