isabelle/valid/mathd_algebra_393.thy (13 lines of code) (raw):

(* Authors: Wenda Li *) theory mathd_algebra_393 imports Complex_Main "HOL-Computational_Algebra.Computational_Algebra" begin theorem mathd_algebra_393: fixes \<sigma>::"real \<Rightarrow> real" assumes "bij \<sigma>" and "\<forall> x. \<sigma> x = 4 * x^3 + 1" shows "inv \<sigma> 33 = 2" sorry end