What is the equation of the graph below?

Step-by-step explanation:

We are a given a graph from which we can clearly see that y = -1 when x  = 0.

Next, to find out which of the options is the equation of the given graph, we need to set our calculator to the radian mode and then we will put the value of x to be 0.

1. y = cos(x + pi/2) = cos(0 + pi/2) = 0

2. y = cos(x+2pi) = cos(0+2pi) = 1

3. y = cos(x+pi/3) = cos(0+pi/3) = 1/2 = 0.5

4. y = cos(x+pi) = cos(0+pi) = -1

We get y = -1 when x = 0 in equation number 4, y = cos(x+pi) = cos(0+pi) = -1. so that is the equation of the given graph.

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step-by-step explanation: