Question

sinx +2sinx=0

Answer 1

\[\sin x + 2\sin x=0\]
Can you simplify this a bit?

Answer 2

well i know 2sinx turns into 2sinxcosx

Answer 3

and you can factor out a sinx

Answer 4

I am just stumped when you

Answer 5

have sinx=0 what is the other part?

Answer 6

Oh, so it's sin 2x?

Answer 7

yah

Answer 8

can you help?

Answer 9

sinx ( 1 + 2cosx) = 0
you are getting till here right ?

Answer 10

yes

Answer 11

so then cos x would = -1/2?

Answer 12

thats right

Answer 13

I am assuming you have got your answers?

Answer 14

i have another question on this one

Answer 15

you may ask .

Answer 16

sin x + 2sinx =0 is eqivilant to what equation?

Answer 17

never mind i figured that one out

Answer 18

am glad you did :|

Answer 19

what about this one

Answer 20

2sin\[2\sin ^{2}\theta + \cos \theta=1\]

Answer 21

do you know what equals 1- 2sin^2 x ?

Answer 22

cos^2?

Answer 23

1 - sin^2 x = cos^2 x

I am asking 1- 2sin^2 x = ?

Answer 24

i am not quite sure of the answer

Answer 25

you know the identity of cos2x ?

Answer 26

cos^2x-sin^2x

Answer 27

thats right
if you substitute 1- sin^2 x in place of cos^2 x in the given identity, you will also get
cos2x = 1- 2sin^2 x

are you following ?

Answer 28

yes

Answer 29

so your given question was
2 sin^2 x + cosx = 1

bring that 2 sin^2x on right side.. see if this helps your case

Answer 30

but what does that 2 do when you bring it over to the other side? I am confused

Answer 31

it becomes this :

cosx = 1- 2sin^2 x

Answer 32

but we have to set the equation to zero to find the answers right

Answer 33

yes we are getting there slowly,
but first do you understand we will have
cosx = cos2x ?

Answer 34

okay. then what?

Answer 35

??

Answer 36

cosx - cos2x = 0

you must be knowing identity of cosa - cosb ?

Answer 37

??