Question

Find all solutions to the equation.

sin2x + sin x = 0

Can someone help me please?

Answer 1

to find x value?

Answer 2

i think so

Answer 3

why not just factor out sinx

Answer 4

i just realized i typed that wrong, it's sin^2x+sinx=0

Answer 5

\[\sin^2x+sinx=0\]
\[sinx(sinx+1)=0\]

Answer 6

\[sinx=0 \]

Answer 7

so sinx=0 and-1?

Answer 8

\[sinx+1=0\]

Answer 9

\[sinx=-1\]

Answer 10

did they give a restriction? example 0 to 2pi

Answer 11

no, there is no restriction

Answer 12

now look for where sinx=0 and sinx=-1

Answer 13

then you need all solutions

Answer 14

\[x=3/2\pi \]

Answer 15

x= pi, x=3/2pi

Answer 16

+2pik so that it has all of the solutions

Answer 17

recall the period for sinx is 2pi
so 2(pi)k will take care of all of the possibilities

Answer 18

so would it be x=pi + 2(pi)k, x= 3/2pi + 2(pi)k

Answer 19

I believe so, I think you can also include - so + and -

Answer 20

ok thank you!!

Answer 21

http://www.wolframalpha.com/input/?i=solve+sin%5E2x%2Bsinx%3D0

Answer 22

ok according to wolframalpha leave off the - just 2 pi (k)

Answer 23

ok, thank you :)

Answer 24

yw