## snivvles.com one year ago find solutions between 0 and 2pi 7 sin2x - 14 sin x + 2 = -5 will fan and medal

1. snivvles.com

so far i've subtracted 2 from each side and divided by 7 to get sin^2x-2sinx=1

2. snivvles.com

@enchanted_bubbles @Peaches15

3. Nnesha

divided by 7 ?? why ?

4. Nnesha

this is like quadratic equation let sinx = x

5. Nnesha

$\huge\rm 7x^2-14x+7=0$ now find GCF and then factor it let sinx = x

6. snivvles.com

to simplify the equation, because all three numbers where divisible by 7

7. snivvles.com

oh

8. Nnesha

ohh right you mean GCF

9. snivvles.com

i got x^2 -2x=0

10. Purplemexican
11. Nnesha

correct so you will get $\huge\rm \frac{ 7x^2 }{ 7}-\frac{ 14x }{ 7}+\frac{ 7 }{ 7 }=0$

12. Nnesha

7/7 = ??

13. snivvles.com

1

14. Nnesha

yes right so it's x^2 -2x +1 =0

15. snivvles.com

OH right

16. Nnesha

after factor it ot 7(x^2-2x+1)=0 now set it equal to zero $7\cancel{=}0 ~~~~x^2-2x+1=0$ now factor x^2-2x+1=0

17. snivvles.com

ok gimme a sec

18. Nnesha

:=)

19. snivvles.com

(x+2) (x-1)?

20. Nnesha

nope 2 times -1 = -2 but it suppose to be one find two number when you multiply them you should get 1 and when you add or subtract them you should get -2

21. snivvles.com

(x+2)(x-1)=0

22. snivvles.com

ok

23. Nnesha

easy method to factor quadratic equation find two number when you multiply them you should get product of AC and when you add or subtract them you should get middle term a=leading coefficient b=middle term c=constant term

24. snivvles.com

hang on a sec

25. snivvles.com

(x-1)^2

26. snivvles.com

?

27. Nnesha

yep right -1 times -1 = 1 -1-1=-2

28. Nnesha

now change it back to sinx you get (sinx -1)^2=0 solve for sin x

29. snivvles.com

I need to find the answers in between (0,2pi)

30. snivvles.com

using the unit circle

31. Nnesha

yep so sinx -1= 0 solve for sinx sinx =1 right ? use unit circle to find radian where sinx = 1

32. snivvles.com

ok that's what i thought thank you so much!

33. Nnesha

my pleasure!