# One On One

**Calculus**Level 4

If \( F(x): \mathbb R \to \mathbb R\) is a one-to-one continuous and differentiable function then which of the following is always true?

**(1)**: \(F'(x)\) must be strictly decreasing or strictly increasing for all \(x\).

**(2)**: \(F'(x)\) can be equal to 0 for some continuous domain of \(x\).

**(3)**: \(F'(x)\) can be equal to 0 for some discrete values of \(x\).

**Notation**: \(\mathbb R \) denotes the set of real numbers.