The least positive integer n for which (1+i1−i)n=2π(sec−11x+sin−1x),x≠0,−1≤x≤1 is:
2
6
8
4
sec−1(1x)+sin−1x=cos−1x+sin−1x=π2
∴(1+i1−i)n=1⇒[(1+i)22]n=in=1
⇒ least n = 4