Hey guys,

allright so I have this question for math that my teacher gave me:

cos 360 = 1

cos 180 + cos 360= 0

cos 120 + cos 240 + cos 360 = 0

cos 90 + cos 180 + cos 270 + cos 360 = 0

cos 72 + cos 144 + cos 216 + cos 288 + cos 360 = 0

a) whats the pattern here?

b) what formula/equation can be made?

if anyone could help that would be good