Concave Real Function/Examples/Cube Function on Negative Reals

Example of Concave Real Function

The real function defined as:

$\forall x \in \R: \map f x = x^3$

is concave where $\R \le 0$.

Sources

• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): convex function