Question 157
Find all polynomials $p$ of odd degree with real coefficients which satisfy
$$
p(p(x)) \le (p(x))^3
$$
for all $x \in \mathbb{R}$ and have the coefficient at $x^2$ equal 0.
$$
p(p(x)) \le (p(x))^3
$$
for all $x \in \mathbb{R}$ and have the coefficient at $x^2$ equal 0.