Let x-,2,3, 4, 5, 6, 7, 8 and let t be a topology on x. let a- , 3, 5,7 (a). find all closed sets in t. (b). find neighborhoods of 1 and 7 (c). find int(a) (d). find a. (e). find aa(boundary of a). (f). is t hausdorf?

Which sum or difference identity would you use to verify that cos (180° - q) = -cos q? a.) sin (a -b) = sin a cos b – cos a sin b b.) cos (a -b) = cos a cos b – sin a sin b c.) cos (a -b) = cos a cosb + sin a sin b d.) sin (a + b) = sin a cos b + cos a sin b