Trigonometric function question

Question

Find a possible formula for the trigonometric function whose values are in the following table.

In ordered pair: (0,-3),(4,-7),(8,-3),(12,1),(16,-3),(20,-7),(24,-3)

Answer 1

f(x) = 8cos²(πx/16 + π/4) - 7 or

f(x) = 4cos(πx/8 + π/2) - 3 = - 4sin(πx/8) - 3