dekh eibhabe inverse trigonometry r sums koris....(doing these after a loong time so pardon me if am wrong)....
case I:
sine-1sine(x)=x ;-∩/2≤x≤∩/2
case II
when Î /2<=x<=3Î /2
add or subtract suitably so that we bring a region within -∩/2 and∩/2....
here let us subtract -∩...
-∩/2≤x-∩≤∩/2 but sine(x-∩)=-sinx so we instead multiply by -1 andtake..
-∩/2≤∩-x≤∩/2 check sine (∩-x)=sinx
case III:
-5Î /2<= x<= -3Î /2
add 2∩
-∩/2≤x+2∩≤∩/2 sine(x+2pi)=sine x