In what quadrant (1,2,3,4) does the point (8,-9) lies

4 because x is positive and y is negative

Quadrant 4

Step-by-step explanation:

Basically to find the quadrant numbers it's a "c"

(-x,y) | (x,y)

2 | 1

(-x,-y) | (x,-y)

3 | 4

From photo you would choose B and D.
Your options make no sense.

tan(x) = sin(x) / cos(x) so the domain is restricted by excluding x where cos(x) = 0
This happens when x = pi/2 and repeats every pi after that = pi/2 + n x pi where n is an integer
I don’t like the wording of B but it is the best definition of domain in the question.