Question

Find all solutions to the equation.

7 sin2x - 14 sin x + 2 = -5

Answer 1

@Kainui @sleepyjess

Answer 2

@mayankdevnani @Atsie @AaronAndyson @Anna1448 @Ashely14 @Bobo-i-bo @birdy258 @carolina4567

Answer 3

@Zenmo @4815162342

Answer 4

4.8

Answer 5

that's the answer?

Answer 6

probably

Answer 7

@Qwertty123 can you help?

Answer 8

how do you know?

Answer 9

I used the calculator

Answer 10

Delete all your replies, I did the equation wrong.

Answer 11

i just did @Zenmo

Answer 12

Hmmm, so the simpliest/brute method would be to:
\[7sin(2x)-14sinx+2=-5\]
\[14sinxcosx-14sinx=-7\]
\[14\sqrt{1-sin^2x}sinx=14sinx-7\]
\[14^2(1-sin^2x)sin^2x=(14sinx-7)^2\]
Then just expand and simply and see if you can solve the resulting quartic polynomial

Answer 13

I think it is sin squared x

Answer 14

how do i expand?

Answer 15

It is quadratic equation ,

Answer 16

I'm on phone can't type

Answer 17

Set the equation equal to and then solve the quadratic equation

Answer 18

Equal to 0*

Answer 19

Equal to 0*

Answer 20

7sin^2x-14sinx +2 +5=0

Answer 21

Let sin x=y, 7y^2 - 14y+7=0 , take out the common factor & factor

Answer 22

@olivya999 here in OS we like learn you how you can solving same exercises not direct answers - ok . ?

Answer 23

Okay learn me @jhonyy9

Answer 24

ok. so how have wrote to you above @Nnesha you sign sin x = y and will get one quadratic in y what you need solve it for y
do you can solve it please ?

Answer 25

Y=1 @jhonyy9

Answer 26

so than this is right you need push

sin x = 1
and calculi the value of x