Take the deritive y'=-3sinx find whre it equals 0 it equals 0 at -pi, 0, pi, etc find whre it changes from negative to positive at -0.5pi, the derivitive is positive at 0.5pi, the deritivie is negative changes from positive to negative at x=0 that means that the max values are at pi and -pi in 2pi intervals
-pi, pi, 3pi, 5pi,etc the min y value is -3
so the minimum(s) are/is at (2aπ,-3) where 'a' is an integer
