+-1±1. It is 1, if a = arc cos (sqrt 2/2)a=arccos(√22) is restricted to be in the 1st quadrant...
Explanation:
Let a=arc cos (sqrt 2/2)=arc cos (1/sqrt 2)a=arccos(√22)=arccos(1√2). As cos (+-a)= cos a, a is in the 1st quadrant or in the 4th. Accordingly, sin a = +-1/sqrt 2 and, therefore, tan a =+-1.
if a = arc cos (sqrt 2/2) is restricted to be in the 1st quadrant. the given expression tan a = 1...