Question

Solutions for 3cosx=cosx-1

domain=0<=x<2pi

Answer 1

should there be 4 solutions...?

Answer 2

1 per quadrant?

Answer 3

@dan815

Answer 4

Nope! There should be 2 solutions tops

Answer 5

quadrant 2 and 3?

Answer 6

Yep! On the right track.

Answer 7

Do you need a hint?

Answer 8

ok

Answer 9

3cosx=cosx-1
2cosx=-1
cosx = -1/2 right?

Answer 10

mhm

Answer 11

So we are looking for the angle that gives us the point where x = -1/2

Answer 12

Do you have a unit circle on you?

Answer 13

yes

Answer 14

Look at the points where x is 1/2

Answer 15

2pi/3

Answer 16

is that theta 60?

Answer 17

and there is another one

Answer 18

what angle is this on a 30-60-90?

Answer 19

Dont get ahead of yourself! Find the other angle too!

Answer 20

i'm just asking what angle its on a 30-60-90..we won't have unit circles on a test.

Answer 21

Yeah I memorized the circle. Um look at it like this

Answer 22

60, got it.

Answer 23

if the question was cosx=1/2?

Answer 24

4 solutions?

Answer 25

We know this because the coordinates are -1/2 , sqrt(3)/2

Answer 26

No 2 solutions

Answer 27

Given that 0 > theta > 2pi

Answer 28

Do you understand why?

Answer 29

has to be in the positive quadrants, right

Answer 30

Yup