grandes-ecoles 2012 QVI.A

grandes-ecoles · France · centrale-maths1__psi Proof Deduction or Consequence from Prior Results
In this part, $\lambda(t) = t$ for all $t \in \mathbb{R}^+$.
Let $g$ be a continuous application from $[0,1]$ to $\mathbb{R}$. We assume that for all $n \in \mathbb{N}$, we have $$\int_0^1 t^n g(t)\,dt = 0.$$
VI.A.1) What can we say about $\displaystyle\int_0^1 P(t)g(t)\,dt$ for $P \in \mathbb{R}[X]$?
VI.A.2) Deduce from this that $g$ is the zero application.
In this part, $\lambda(t) = t$ for all $t \in \mathbb{R}^+$.

Let $g$ be a continuous application from $[0,1]$ to $\mathbb{R}$. We assume that for all $n \in \mathbb{N}$, we have
$$\int_0^1 t^n g(t)\,dt = 0.$$

VI.A.1) What can we say about $\displaystyle\int_0^1 P(t)g(t)\,dt$ for $P \in \mathbb{R}[X]$?

VI.A.2) Deduce from this that $g$ is the zero application.