Question 865985
{{{ graph( 300, 200, 0, 13, -1, 1, cos(x) ) }}}
note that pi = 180 degrees, therefore the interval in degrees is [0, 720]
the cosine of 60 degrees is 1/2
we convert degrees to radians = degrees * pi/180
60 degrees = pi/3 radians
from the graph, we see the following
the angles theta in radians are pi/3, 5*pi/3, 7*pi/3, 11*pi/3