## logynklode 3 years ago 7 sin2x - 14 sin x + 2 = -5 find all solutions

1. rvgupta

cosx=-1

2. logynklode

thats not even english to me.

3. rvgupta

ok

4. hba

@hartnn

5. logynklode

7sin²(x) - 14sin(x) + 2 = -5 7sin²(x) - 14sin(x) + 7 = 0 7(sin²(x) - 2sin(x) + 1) = 0 sin²(x) - 2sin(x) + 1 = 0 (sin(x) - 1)² = 0 sin(x) - 1 = 0 sin(x) = 1 x = 90°

6. logynklode

would it be that?

7. hartnn

is it sin2x or \(sin^2 x\) ??

8. logynklode

sin squared x

9. hartnn

then sin x=1 is correct. but do u need solutions in the range of 0 to 180 only or all solutions ?

10. logynklode

no idea. the question say find all solutions to the equation

11. hartnn

because sin (360+90) also =1

12. hartnn

yes, all solutions means u don't have only 1 solution, u have infinite

13. logynklode

alright

14. hartnn

sin(x)=1 sin x = sin (90+360n) (n=1,2,3,....) so x= 90+360n are all the values of x with n=1,2,3,....`

15. hartnn

got that ^ ?

16. logynklode

17. hartnn

yes.

18. logynklode

you sure. i can wrrite that & ill be correct?

19. logynklode

if i wrote exactly what you just put down ill be correct?

20. hartnn

idk how your teacher / system demands the answer, but any of these 2 answers are complete and correct: 1) x= 90+360n , n=1,2,3,..... 2) x=90,450,810,..

21. hba

Whats The Range ? I think It Would Be 0 to 180

22. logynklode

thanks