Question

See Attached!!!

Answer 1

I eliminated the choices to A and D.

Answer 2

isolate cos \(\theta\)

Answer 3

I did and go cos(x)= -1/2

Answer 4

*got

Answer 5

good, now for which angles is cos \(\theta\) = -1/2 ?

Answer 6

I feel the answer should be 2pi/3 and 5pi/3

Answer 7

2pi/3 correct :)
sin (5pi/3) = +1/2

Answer 8

**cos (5pi/3)

Answer 9

Oh.... So the answer is D. 2pi/3 and 4pi/3?

Answer 10

how about cos (4pi/3) = ..?

Answer 11

yes :)

Answer 12

Thank you!!! How is cos(5pi/3)=0?

Answer 13

I mean -1/2

Answer 14

cos (5pi/3) = cos (pi+2pi/3) = - cos (2pi/3) = - (-1/2) = +1/2 actually

Answer 15

Thank you! Thank you for all your help. I was able to get a 100% on my homework with your help!

Answer 16

great!

Answer 17

welcome ^_^