Question

Solve the equation on the interval [0, 2π).

cos x + 2 cos x sin x = 0

Answer 1

@AnswerMyQuestions

Answer 2

1.
2 cos x − sin² x = cos² x
2 cos x = sin² x + cos² x
2 cos x = 1
cos x = 1/2

Answer 3

I would factor out cosx from both terms
cosx(1+2sinx)=0
then set each term to zero
cosx=0 1+2sinx=0

Answer 4

so @victorhernandez what would the answer be?

Answer 5

solve for x in each case and then recall that your domain is only from 0 to 2pi

Answer 6

I don't know what victorhernandez did but it doesn't look correct unless he rewrote it using identities.

Answer 7

:3

Answer 8

That is what i was thinking @precal he didnt write it right

Answer 9

http://www.thattutorguy.com/unit-circle-pdf/
you can look up the values on this pdf but any trig table or unit circle will work

Answer 10

cosx=0
look at the circle and look at the x values
x values are cosine and y values are sine
look for (0, number)
then look at the degrees or radians where x is 0

Answer 11

1+2sinx=0
2sinx=-1
sinx = -1/2
look at the y values and look for -1/2 and that will give you the solutions for sinx=-1/2

Answer 12

is it pi/2, 7pi/6, 3pi,2,11pi/6

Answer 13

let me double check

Answer 14

yes that is correct

Answer 15

YAY! lol Thank you

Answer 16

ok but more important did you understand it because then you can do other problems as well.

Answer 17

yes

Answer 18

yw