Function and graph
\(y= x^3+3|x|+c\) is a function.
Which of the following statements is/are true?
1. If \(-2\leq c\leq 0\), then \(y\) has at least two roots.
2. If \(0\leq c\leq 2\), then y has at most one root.
3. If \(f'(b)=0\), \(b\) is the root of \(y\), then \(c = 2\).
4. \(y\) is decreasing in \(y \in (a,b)\) and \(b-a=2\).