\ \

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 = \ \

Find the positive angle ,subtract to obtain a co-terminal angle \ \

\ \

Find the 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 .