Respuesta :

Standard Equation for trig function: y = A cos (B (x - H))+ K
*Here, we are just dealing with A (amplitude) and B (period)
Period = 2π/ b

8 = 2π/ b
Solve for b: 2π/8 or π/4

Equation: y = 2 cos (π/4 (x))
RELAXING NOICE
Relax