Question

fan+medal see pic

Answer 1

pic

Answer 2

@4everaddicted2anime @supersmart1001 @mathstudent55 @SamandDean1967 @anthonyym @AnitaS.

Answer 3

@Atrineas

Answer 4

I haven't learned how to use cos I'm sorry >~<

Answer 5

can u try

Answer 6

@jdoe0001 @shaleiah

Answer 7

Ok you can rearrange the equation so that cosx = -sqrt2 / 2

Answer 8

okay?

Answer 9

Then look on the unit circle to see where cosx = -sqrt2 / 2

Answer 10

??

Answer 11

@bmk614 @Nnesha

Answer 12

is it b?

Answer 13

@mathstudent55

Answer 14

does anyone know the answer to this?

Answer 15

@josedavid @johnweldon1993

Answer 16

Do you understand everything what I said?

Answer 17

yeah sorta

Answer 18

Do you understand how I rearranged the equation to get \[cosx = \frac{ -\sqrt{2} }{ 2 }\]

Answer 19

yeah i get that

Answer 20

Do you know the unit circle?

Answer 21

um sorta

Answer 22

https://en.wikipedia.org/wiki/Unit_circle#/media/File:Unit_circle_angles_color.svg

Answer 23

yeah i get that i just want to know if my answer is right or not

Answer 24

No, it's not b because the domain is restricted to [0, 2pi), so you can't have +2pi(n), but the 3pi/4 is right

Answer 25

so its A?

Answer 26

If you look on the unit circle (the above link), it has coordinates (x,y).
cosine of that angle is x, and sine of that angle is y.
You can think of it as
(x, y)
(cos, sin)

Answer 27

so c?

Answer 28

Yes c is correct. On the unit circle, both cosine of 3pi/4 and 5pi/4 yield -sqrt2 / 2

Answer 29

ty

Answer 30

np