(a)

The angle is .

For the positive angle , subtract to obtain a co - terminal angle.

.

For the negative angle , add to obtain a co - terminal angle.

.

(b)

The angle is .

For the positive angle , subtract to obtain a co - terminal angle.

.

For the negative angle , add to obtain a co - terminal angle.

.

(a) The positive angle is and negative angle is .

(b) The positive angle is and the negative angle is .