4 is the highest common factor (HCF) of each
of the following except
A 4 dan/and 12
B 8 dan/and 28
C 4, 16 dan/and 36
D 20,80 dan/and 120

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.