.
The domain of  is where tan(x) is DEFINED and where tan(x) is non-negative.
tan(x) is non-negative in the first and the third quadrants.
Therefore, the domain of
  is where tan(x) is DEFINED and where tan(x) is non-negative.
tan(x) is non-negative in the first and the third quadrants.
Therefore, the domain of   is
    (a)
  is
    (a)   <= x <
 <= x <  ,  n = 0, +/-1, +/-2, . . .    (1-st quadrant)
and
    (b)
,  n = 0, +/-1, +/-2, . . .    (1-st quadrant)
and
    (b)   <= x <
 <= x <  n = 0, +/-1, +/-2, . . .    (3-rd quadrant)
  n = 0, +/-1, +/-2, . . .    (3-rd quadrant)
Solved.