(** ** arcsine of specific values *)

(* Specifications: *)
Lemma asin_0 : asin 0 = 0.
Lemma asin_1 : asin 1 = PI / 2.
Lemma asin_inv_sqrt2 : asin (/sqrt 2) = PI/4.
Lemma asin_opp : forall x,
asin (- x) = - asin x.