Definition alphas_p : R -> R := d2 alphas.

Lemma D_Rs_alphas1 : forall t : R, derive_pt (fun y : R => (Rs y * derive_pt alphas y (cond_D1 alphas y))%R) t (fct_der5 t) = (derive_pt Rs t (Rs_derivable t) * derive_pt alphas t (cond_D1 alphas t) + Rs t * derive_pt (derive alphas (cond_D1 alphas)) t (cond_D2 alphas t))%R.