Question

Trigonometry question!

Answer 1

Find the following value for θ such that 0≤ θ<2π
cos θ = -1/2

Answer 2

So it's either in the second or third quadrant, and it's a 45-45-90 triangle

Answer 3

For this question, you need to look at a unit circle to figure it out. When is cosine -1/2 in the second quadrant?

Answer 4

Also, your profile picture rocks :3

Answer 5

I got 120 degrees, but i dont really know how to get there...

Answer 6

Okay, so when cosine is -1/2, you look at your unit circle and you can see that at 120 degrees, the coordinates are (-1/2, \[\sqrt{3}\]/2). The x value is cosine, and the y value is sine.

Answer 7

i just guessed and checked
(thanks! :^) )

Answer 8

You're totally welcome!