If the number of photos ordered is more than 99 and fewer than 200 each photo cost 0.17 and there is a $4.50 shipping fee of 200 or more photos are ordered each photo cost 0.15 and there's no shipping fee what is the piecewise define function that expresses the cost of the order in terms of the number of photos ordered

Period is the time it takes for one “cycle” to complete. in the parent sine function, period is 2*pi since sin(0) = 0, sin(pi/2) = 1, sin(pi) = 0, sin(3pi/2) = -1, and sin(2pi) = 0. at that point, the sequence repeats itself. i’m not sure if your graph is similar to the sine function since you didn’t provide a picture, but you can find the period by looking at a graph.