JEE-Advanced 2014 (1/40)

Algebra Level 3

If \(a\in \mathbb R\) and \(f:\mathbb R \to \mathbb R\) is given by \(f(x)=x^5-5x+a,\) then which of the followings is/are true?

A. \(\ \, f(x)\) has three real roots if \(a>4\).
B. \(\ \, f(x)\) has only one real root if \(a>4\).
C. \(\ \, f(x)\) has three real roots if \(a<-4\).
D. \(\ \, f(x)\) has three real roots if \(-4<a<4\).