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Lulu212

  • 2 years ago

Solve sin2x + 4sin x + 3 = 0

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  1. Lulu212
    • 2 years ago
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    do u know how to solve this ?

  2. jeanlouie
    • 2 years ago
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    sin(2x) is more interesting :)

  3. Omniscience
    • 2 years ago
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    Is it sin^2x + 4sinx + 3 = 0 ?

  4. Omniscience
    • 2 years ago
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    |dw:1345778720492:dw| i dont know why latex is not working..

  5. ash2326
    • 2 years ago
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    @Lulu212 Is it \(\sin 2x \ or \ \sin^2 x\)?

  6. Lulu212
    • 2 years ago
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    sin 2x

  7. Mimi_x3
    • 2 years ago
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    \[sin2x + 4sinx + 3\]

  8. Mimi_x3
    • 2 years ago
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    \[sin2x = 2sinxcosx\] \[ 2sinxcosx + 4sinx + 3 = 0 \]

  9. Mimi_x3
    • 2 years ago
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    have you tried that yet?

  10. Yahoo!
    • 2 years ago
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    hm...hm.... u need...to find the General soln of this....!

  11. Yahoo!
    • 2 years ago
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    @UnkleRhaukus @Hero @jim_thompson5910 @myininaya

  12. Yahoo!
    • 2 years ago
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    @Hero @hartnn

  13. UnkleRhaukus
    • 2 years ago
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    \[ \sin(2x) + 4\sin (x) + 3 = 0\] \[ 2\sin(x)\cos(x) + 4\sin (x) + 3 = 0\] \[2\sin (x)\left(\cos(x)+2\right)+3=0\] \[2\sin (x)\left(\cos(x)+2\right)=-3\] \[\cos(x)+2=\frac{-3}2\csc(x)\] i dont know

  14. Yahoo!
    • 2 years ago
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    @satellite73 @saadi

  15. Hero
    • 2 years ago
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    I don't understand why @UnkleRhaukus can't finish it

  16. Yahoo!
    • 2 years ago
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    Can u Finish @Hero i am also stuck..there

  17. Yahoo!
    • 2 years ago
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    @jim_thompson5910

  18. Mimi_x3
    • 2 years ago
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    hmm http://www.wolframalpha.com/input/?i=sin2x+%2B+4sin+x+%2B+3+%3D+0 i dont think its possible..

  19. Yahoo!
    • 2 years ago
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    i think..tthere is mistake in question..))))

  20. Yahoo!
    • 2 years ago
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    @Lulu212 can u check ur question...))

  21. Mimi_x3
    • 2 years ago
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    I think it should be \(sin^2x + 4sinx +3 =0\)

  22. Mimi_x3
    • 2 years ago
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    then \(u=sinx\) more reasonable

  23. Yahoo!
    • 2 years ago
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    then it is a quad eq

  24. Yahoo!
    • 2 years ago
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    we can find sinx

  25. Hero
    • 2 years ago
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    I'm inclined to agree with @Mimi_x3

  26. manishsatywali
    • 2 years ago
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    this question can be solved ............why u guys are worrying????????

  27. nickhouraney
    • 2 years ago
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    it cant be solved just endless ways of writing the equation

  28. panlac01
    • 2 years ago
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    what are we solving for? LOL. that equation needs to be written precisely in a way that we all can agree to what it is.

  29. UnkleRhaukus
    • 2 years ago
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    \[\sin^2x+4\sin x+3=0\] \[u^2-4u+3=0\] \[u=\frac{-(-4)\pm\sqrt{(-4)^2-4\times(1)\times(3)}}{2(1)}\] \[u=2\pm\frac{\sqrt{4}}{2}\]\[u=2\pm1\]\[u=1,3\] \[(1)^2+4(1)+3=0,\qquad\qquad 3^2-4(3)+3=0\]\[8=0,\qquad\qquad\qquad 3^2-4(3)+3=0\]\[\text{false}\qquad\qquad\qquad 9-12+3=0\]\[\qquad\qquad\qquad\qquad0=0\]\[\qquad\qquad\qquad\text{true}\]

  30. panlac01
    • 2 years ago
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    the equation toolbar in this thing sucks hairy ______. how do you write it so neatly like that?

  31. UnkleRhaukus
    • 2 years ago
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    so \(u=\sin(x)=3\) \[x=\arcsin (3)\] ... this question is very confusing \[\text{\[u=\frac{-(-4)\pm\sqrt{(-4)^2-4\times(1)\times(3)}}{2(1)}\]}\]

  32. UnkleRhaukus
    • 2 years ago
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    oh damn my solution is way off \[\sin^2(\arcsin 3) + 4\sin (\arcsin 3) + 3 = 24≠0\]

  33. UnkleRhaukus
    • 2 years ago
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    oh \(u^2+4u+3=0\) NOT \(u^2-4u+3=0\)

  34. nickhouraney
    • 2 years ago
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    but this wasnt the problem that was stated lol

  35. UnkleRhaukus
    • 2 years ago
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    \[u_{1,2}=-2\pm1=-3,-1\]

  36. UnkleRhaukus
    • 2 years ago
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    \[\sin x=u=-3,-1\] \[x_{1,2}=\arcsin (-1),\quad \arcsin(-3)\] \[x_1=-\frac \pi2\qquad, x_2=\text{some transcendental nonsense} \] hence\[x=-\frac {\pi}2\] CHECKING \[\sin^2x + 4\sin x + 3 = 0\] \[\sin^2\left(-\frac\pi 2\right) + 4\sin \left(-\frac\pi 2\right) + 3 = 0\]\[1+4(-1)+3=0\]\[0=0\]true hence \[\large{x=-\frac {\pi}2}\]is the solution to \[\sin^2x + 4\sin x + 3 = 0\]

  37. UnkleRhaukus
    • 2 years ago
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    ta-da

  38. Hero
    • 2 years ago
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    People who post questions need to learn how to use the equation editors to avoid such confusion.

  39. panlac01
    • 2 years ago
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    couldn't agree more @Hero

  40. UnkleRhaukus
    • 2 years ago
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    i think someone needs to write a program that can interpet questions and convert them to \(\LaTeX\) automagically

  41. nickhouraney
    • 2 years ago
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    @lulu212 i am disappoint at this equation

  42. Hero
    • 2 years ago
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    I imagine that something like that would have to be interactive. It would have to be some kind of AI that would automatically ask the user something like: Did you mean \(\sin(2x)\) or \(\sin^2(x)\)?

  43. panlac01
    • 2 years ago
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    beyond OS' capacity :P we can ask Wolfram though. That dude is probably the smartest programmer I've seen alive

  44. Hero
    • 2 years ago
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    That's because he was reincarnated Einstein

  45. panlac01
    • 2 years ago
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    hahaha... I think he was already born when Einstein was still alive

  46. Hero
    • 2 years ago
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    Well, Einstein's lost twin

  47. nickhouraney
    • 2 years ago
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    this question has like 40 responses all because of a typing error

  48. Hero
    • 2 years ago
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    We're still assuming that it is a typing error

  49. nickhouraney
    • 2 years ago
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    it is

  50. Hero
    • 2 years ago
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    There's no such thing as typing errors. Only human errors.

  51. panlac01
    • 2 years ago
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    the person who asked for help did not even say anything after the question was posted (TYPOGRAPHICAL ERROR)

  52. UnkleRhaukus
    • 2 years ago
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    can't we all be einsteins lost twin?

  53. panlac01
    • 2 years ago
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    I know that I can't... I have a roach's brain compare to his

  54. nickhouraney
    • 2 years ago
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    same difference hero lol

  55. UnkleRhaukus
    • 2 years ago
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    twins dont necessarily have the same charistics

  56. panlac01
    • 2 years ago
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    oh that's right... I'd be the opposite of his intellect then

  57. UnkleRhaukus
    • 2 years ago
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    * characteristic

  58. Hero
    • 2 years ago
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    In one of Einstein's lost journals, he wrote that his brain was removed as a kid. The person handling his brain accidentally dropped in brain in a toilet, but quietly removed it without telling anyone. Once the brain was placed back into Einstein's head, he felt different, like as if he had more 'powers' and 'ability'. We all know what that led to.

  59. UnkleRhaukus
    • 2 years ago
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    oh my.

  60. panlac01
    • 2 years ago
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    where's David Hume?

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