它们的反函数也在相应区间单调且连续 y= arcsin x-1≤x≤1 y= arccos x-1≤x≤1 y= arctan x-∞<x<+∞ y=arc cot x -o<x< +o October 2004October, 2004 它们的反函数也在相应区间单调且连续 y x = arcsin −   1 1 x y x = arccos −   1 1 x y x = arctan −   + x y x = arccot −   + x