What is the correct equation for the function whose graph is shown?

a. y = -5 cos 3x
b. y = -3 cos 5x
c. y = 3 cos 5x
d. y = 5 cos 3x

i know its either b or c. but i'm not sure which one relating to the positive/negative 3.

y= 3 cos 5x would be my best educated guess.

step-by-step explanation:

y = | -2(-2) |     →     y = | 4 |     →     y = 4       ⇒   (-2, 4)

y = | -2(-1) |     →     y = | 2 |     →       y =   2       ⇒   (-1, 2)    

y = | -2(0) |     →     y = | 0 |     →       y = 0         ⇒   (0, 0)

y = | -2(1) |   c →     y = | -2 |     →     y =   2         ⇒   (1, 2)    

y = | -2(2) |     →     y = | - 4 |     →     y =   4         ⇒   (2, 4)  

answer: 1 + 1 = 11

step-by-step explanation: