Respuesta :

Answer:

option 1 ⇒ f(x) = cos (4x)

Step-by-step explanation:

The general equation of the given graph is as following

f(x) = A cos (Bx)

Where A is the amplitude

and B = 2π/period

From the graph

A = 1

period = π/2

∴ B = 2π/period = 2π/(π/2) = 4