We denote the
inverse of sine function by sin–1 (arc sine function) Thus, sin–1 is a function whose
domain is [– 1, 1] and range could be any of the intervals 
23 ,
2
− π −π





, 
2,
2
−π π





 or
2,3
2
π
π






, and so on Corresponding to each such interval, we get a branch of the
function sin–1 The branch with range 
2,
2
−π π




  is called the principal value branch,
whereas other intervals as range give different branches of sin–1