Question

unit circle?
http://prnt.sc/djl36k

Answer 1

Can you determine in which quadrant (I, II, III, IV) each of the two given angles lies?

If the two angles were in Q II and QIII, then the cosines would be the same, but under other circumstances they would not be the same.

Answer 2

3 & 4

Answer 3

Right. These 2 angles are in different quadrants. Does that help you to answer the question? In other words, are the two cosines equal or not equal?

Answer 4

the answer is no? i just need to know for which reason. c or d

Answer 5

@mathmale no as in the angles arent

Answer 6

Right; the angles are in different quadrants, and in this particular case that means that the cosines of these angles are different. One is positive and one is negative. Which cosine do you think is positive?

Answer 7

@mathmale 11pi/6?

Answer 8

Very good. "cosine" is defined as (adjacent side) / hypotenuse.
In the 4th quadrant, the adjacent side and the hyp are both positive, which is why your answer is correct.

Answer 9

D?

Answer 10

Perfect. Congrats.

Answer 11

thank you @mathmale