Question

Find the values of x for which the equation cos x=-1 is true. Let k represent an integer.

Answer 1

Can you graph the cosine function? The graph would definitely help you answer this question. Note that you have not shown k.

Answer 2

I am not given a value for k.

Answer 3

cos x is the x coordinate of a point on the unit circle... ( cos x , sin x), when is the x coord -1 what angle

Answer 4

180?

Answer 5

right, the cos of 180 is -1

Answer 6

Here... I don't normally post the options because people give direct answers rather than explanations...

Answer 7

since the radius is 1, the cos(A) = x / 1 , the x coordinate