Write an equation of the form y a sin bx or y a cos bx to

Write an equation of the form y = a sin bx or y = a cos bx to describe the graph below.

Solution

From the graph following facts are drawn

(1) Curve is cosine

(2) The amplitude a = 4 units

(3) The period of a complete oscillation is b = 6 units

Hence, equation of the curve is y = 4 cos ( 6 x )