a).

From the figure angle =.

To find positive angle, subtract to obtain a co - terminal angle

- = .

To find negative angle, add to obtain a co - terminal angle

+ = .

b). From the figure angle =.

To find positive angle, subtract to obtain a co - terminal angle

- = .

To find negative angle, add to obtain a co - terminal angle

+ = .

Therefore,

(a).The positive and negative angle of are and .

(b).The positive and negative angle of   are and .