EulerAngles

EulerAngles[r] gives Euler angles {α,β,γ} corresponding to the rotation matrix r.

EulerAngles[r,{a,b,c}] gives Euler angles {α,β,γ} with rotation order {a,b,c}.

Examples

Get Euler angles from a rotation matrix:

EulerAngles[RotationMatrix[Pi/4, {0, 0, 1}]]
(* {Pi/4, 0, 0} *)

Please visit the official Wolfram Language Reference for more details.