Compute cos(0) + cos(5) + cos(10) + cos(15) + ... + cos(355). (All angles are in degrees.)
+23246 cos(0) cancels out cos(180)
cos(5) cancels out cos(175)
...
cos(85) cancels out cos(5)
This leaves you with cos(90); how much is cos(90)?
cos(355) cancels out cos(185)
cos(350) cancels out cos(190)
...
cos(275) cancels out cos(265)
This leaves you with cos(270); how much is cos(270)?
So, how much is cos(90) + cos(270)?
