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anonymous

  • one year ago

Find all solutions to the equation. 7 sin2x - 14 sin x + 2 = -5

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  1. Nnesha
    • one year ago
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    set it equal to zero then you will get quadratic equation

  2. anonymous
    • one year ago
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    Yeah I noticed that but can you show me how you to set it up

  3. Nnesha
    • one year ago
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    \[\huge\rm 7\sin^2x-14sinx+2+5=0\] add 5 both

  4. Nnesha
    • one year ago
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    to make it easy let sin(x) x \[\huge\rm 7x^2 -14x+2+5 =0\] |dw:1437508829146:dw| solve for x :-)

  5. anonymous
    • one year ago
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    Ohh okay thanks

  6. Nnesha
    • one year ago
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    let me know what you get

  7. anonymous
    • one year ago
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    Yeah just give me a min I need to solve another problem real quick

  8. Nnesha
    • one year ago
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    sure :=)

  9. anonymous
    • one year ago
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    7x^2-14x+7

  10. Nnesha
    • one year ago
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    equal to zero 0 then take out common factor

  11. anonymous
    • one year ago
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    7(x^2-2x+1)=0

  12. Nnesha
    • one year ago
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    opps sorry i didn't get notification

  13. Nnesha
    • one year ago
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    and yes that's right now factor this quadratic equation x^2 -2x +1

  14. anonymous
    • one year ago
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    7(x-1)(x+1)=0

  15. Nnesha
    • one year ago
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    yes right now set these equal to zero \[\huge\rm 7 \cancel= 0 ~~~(x-1)=0~~~(x-1)=0\] solve for x

  16. anonymous
    • one year ago
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    x=1

  17. anonymous
    • one year ago
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    what about the sines though?

  18. Nnesha
    • one year ago
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    yes now change x with sin

  19. Nnesha
    • one year ago
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    remember we changed sin(x) with x right ?

  20. anonymous
    • one year ago
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    oh yeah

  21. Nnesha
    • one year ago
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    so \[\huge\rm sinx =1 \]

  22. Nnesha
    • one year ago
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    now use unit circle to find solution

  23. anonymous
    • one year ago
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    find where one is 1 is y on the unit circle?

  24. Nnesha
    • one year ago
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    (cos , sin) x coordinate represent cos function and y coordinate represent sin function

  25. anonymous
    • one year ago
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    would it be pi/2

  26. Nnesha
    • one year ago
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    |dw:1437510845962:dw|

  27. Nnesha
    • one year ago
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    yep

  28. anonymous
    • one year ago
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    thats it, thats the only solution

  29. Nnesha
    • one year ago
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    yep right

  30. anonymous
    • one year ago
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    oh okay thank you so much!

  31. Nnesha
    • one year ago
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    my pleasure but remember sinx = 1 multiplicity of 2

  32. anonymous
    • one year ago
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    I'm gonna post another question can you help me with that one as well, I think i know the answer just confused how to get to the answer

  33. anonymous
    • one year ago
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    so my answer would be sinx=1^2?

  34. Nnesha
    • one year ago
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    no sin x= 1 is right

  35. anonymous
    • one year ago
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    oh okay

  36. anonymous
    • one year ago
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    so just to confirm, my answer box would read sinx=1

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