Question

FAN AND MEDAL
For what x-value(s) does cos(x) = -1?

-270°, -90°, 90°, and 270°

-270°, -90°, 0°, 90°, and 270°

-180° and 180°

-360°, 0° and 360°

Answer 1

somebody else had this same problem look for it

Answer 2

http://openstudy.com/study#/updates/55831bfee4b0b31a8a3fee1a

if there's anything that's still confusing, feel free to tag me

Answer 3

that is not the same question nor the same equation ??

Answer 4

well, not exactly, but after he simplified he ended up with cos(x) = -1, which is the same as your problem

look at the later parts of the question

Answer 5

Or better still

have a look at the graph of cos (x) from -360 to 360 and see where it is -1

Try to understand the cyclic nature of the cos function...