What is the equation of the graph below? A coordinate plane. The graph starts and rises to (negative 5 pi comma 1). It then falls through (negative 15 pi over 4 comma 0) to (negative 5 pi over 2 comma negative 1). It then rises through (negative 5 pi over 4 comma 0) to (0 comma 1). It then falls through (5 pi over 4 comma 0) to (5 pi over 2 comma negative 1). It then rises through (15 pi over 4 comma 0) to (5 pi comma 1). y = cosine (StartFraction x Over 0.4 EndFraction) y = cos(5x) y = cos(0.4x) y = cosine (StartFraction x Over 5 EndFraction)