Question

Helppp

Answer 1

5. Imagine you are looking for a certain angle whose cosine is positive and whose sine is negative.
Part I: Name the two quadrants in which cosine is positive. (2 points)


Part II: Name the quadrants in which sine is negative (2 points)


Part III: Use the information in parts a and b to identify the quadrant in which cosine is positive and sine is negative. (2 points)


Part IV: Write down one angle, in degrees, that has a negative sine and a positive cosine. (2 points)




Part V: Using your calculator, confirm your choice by writing the cosine of your angle and the sine of your angle below. (4 points)

Answer 2

part I: any thoughts so far? as a hint we would want the quadrants where x is positive

Answer 3

first and third

Answer 4

you're very close but not quite

it would have to be the "right half" of unit circle

Answer 5

first and second

Answer 6

oh one and four

Answer 7

awesome

what about II) where sin is negative?

Answer 8

*part II

Answer 9

third

Answer 10

good but there's one more where sin is negative, as a hint the entire bottom half of the unit circle has negative sin

Answer 11

third and fourth

Answer 12

awesome

for part III) we want positive cos and negative sin, and according to our answers from before, the only quadrant that shares both these qualities is Q4 since its in both our lists

so quadrant IV

Answer 13

Part IV: Write down one angle, in degrees, that has a negative sine and a positive cosine. (2 points)

just need to write down an angle in quadrant IV, it has to be greater than 270 and less than 360 degrees, anything between that is fien

Answer 14

300

Answer 15

good

then for part V just plug your angle into a calculator and confirm that cos (theta) is positive and sin (theta) is negative

Answer 16

(just need to copy the calculator output)

Answer 17

okay

Answer 18

like this

Answer 19

oh, you need to calculate them separately not together

so calculate cos(300) and then sin(300) separately, then just copy the outputs

Answer 20

1/2 and -sqrt3/2

Answer 21

good, that's it for part V