Question

WILL GIVE MEDAL!!!

Assume theta is a angle in standard position and cos theta equals -1/2 and sin theta = -(radical 3)/2 . Can the value of theta possibly be 60? Can it possibly be -120? Please draw diagram and please explain.

Answer 1

@billj5

Answer 2

i would start by drawing it and label what you are given first

Answer 3

Idk how to label any of this, this topic is very confusing...

Answer 4

honestly its best to just memorize different values of the unit circle

Answer 5

but you should understand what quadrants sin is positive or negative and what quadrants cos is positive or negative

Answer 6

I know which quadrants the trig functions are positive it. I just don't know the different values is all.

Answer 7

oh ok, well its easiest just to memorize in my opintion

Answer 8

google unit circle, click on images and you will see plenty of them labeled with angles and their values

Answer 9

http://etc.usf.edu/clipart/43200/43217/unit-circle9_43217_lg.gif

Answer 10

perfect

Answer 11

and we know cos (theta) is x and sin (theta) is y right?

Answer 12

Yes

Answer 13

well this problem is really asking you to know when sin and cos are negative what quadrant the angle is in

Answer 14

in this case both sin and cos are negative so that should be Q3

Answer 15

so is the angle 60 in Q3?

Answer 16

no, its in Q1 right?

Answer 17

yes

Answer 18

Angle 60 is quarter 1

Answer 19

so it cant possibly be 60

Answer 20

now what quadrant is -120 in?

Answer 21

2

Answer 22

no,

Answer 23

-120 + 180 = 60 . my bad, quad 1

Answer 24

no

Answer 25

-120 + 360 , quad 3?

Answer 26

its easiest for me to think going clockwize when dealing with negative angle, yes Q3

Answer 27

so, since we are looking for an angle in Q3 and -120 is in Q3 then it could "possibly" be those values, thats all the question is asking, its not asking if it actually is that value

Answer 28

but it is in fact that value

Answer 29

So what would be the answer and how would the diagram look like?

Answer 30

i would draw the unit circle and the x and y axis, and show somehow where sin and cos are positive or negative, and show which quadrant the angles lie in, draw the angles

Answer 31

How would I explain how i got the answerrr