Thus, g–1 = (f –1)–1 = f We also have
(f –1 o f ) (x) = f –1 (f (x)) = f –1(y) = x
and
(f o f –1) (y) = f (f –1(y))  = f (x) = y
Since the domain of sine function is the set of all real numbers and range is the
closed interval [–1, 1] If we restrict its domain to
2,
2
−π π





, then it becomes one-one
and onto with range [– 1, 1] Actually, sine function restricted to any of the intervals
−

23
2
π
, �π
,
2,
2
−π π





, 
2,3
2
π
π






etc