intuition.
simpl in *.
rewrite plus_0_r.
eapply le_trans.
2:{
eapply expnat_base_S.
}
destruct n; simpl.
omega.
intuition.
Qed.

(* Specifications: *)
Lemma sqrt_le_lin_gen : forall a b,
(a <= b ->
Nat.sqrt a <= b)%nat.