Question

calcule usando arcos congruos:
a) cos 9π/4
b) cos(-330°)
c) cos 9π/2
d) cos 1140°

Answer 1

cos 9pi/4 = 
cos 9.180/4 = 
cos 9.45 =
cos 405 = ...
405/360 = 1 e sobram 45
cos 45 = \/2/2
cos 9pi/4 = \/2/2