hey, can someone tell me how to do these? like explain it and all

Find the domain and range of:

a)

do for y = 2tanx.. the domain would be -pi/2 < x < pi/2

the range is all real y

so for to domain should be all real x

and range should be -pi/2 < x < pi/2

But the book said that the range should be -pi< x < pi

I don't get why.

b)

I don't understand this one at all

THANKS IN ADVANCE :)