Errors: {
  Method not found: 'acos'. (@0)
}
method /* from org-dartlang-debug:synthetic_debug_expression */ debugExpr() → dynamic
  return throw new dart.core::NoSuchMethodError::withInvocation(null, new dart.core::_InvocationMirror::_withType(#acos, 32, const <dart.core::Type>[], dart.core::List::unmodifiable<dynamic>(<dynamic>[1.0]), dart.core::Map::unmodifiable<dart.core::Symbol, dynamic>(const <dart.core::Symbol, dynamic>{})));