Let
be the real polynomial function,
Prove that if
for all
such that
then
%V0
Let $P(x)$ be the real polynomial function, $P(x) = ax^3 + bx^2 + cx + d.$ Prove that if $|P(x)| \leq 1$ for all $x$ such that $|x| \leq 1,$ then
$$|a| + |b| + |c| + |d| \leq 7.$$
Školjka