Write the equation of a sine or cosine function to describe

Write the equation of a sine or cosine function to describe the graph.

Solution

cosx funtion has mximum at x= 0.In this graph the maximum point is shifted by 2 units to left

Period = 6 - (-2) = 8

amplitude = (6 - (-2))/2 = 4

midline: y =2

Standard cosine function : y = Acos(Bx +C) +D

y = 4cos(pix/4 +pi/2) + 2