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Math Help - Solve Equation - - Does this look right?

  1. #1
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    Solve Equation - - Does this look right?

    Hi there,

    My question is:

    Solve Equation
    4sin(x)^2 + 7sin(x) = 2

    Here is what I did:

    4sin(x)^2 + 7sin(x) -2 = 0
    (4sinx - 1)(1sinx + 2) = 0

    4sinx -1 = 0 or Sinx +2 =0
    sinx = (1/4) Sinx = -2


    I multiplied both sides of each equation by the inverse of sin resulting in:

    Sinx = (1/4) at 0.25 radians - (14.48 degrees) in quadrant one, and 104.47 degrees in quadrant two (90 degrees + 14.48 = 104.48 degrees)

    Sinx = -2 is not possible - no solution.

    My professor has never used obscure degrees like this before, so I'm wondering if I'm doing something wrong. Any suggestions?

    Thanks in advance!

    PurplePonies
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  2. #2
    MHF Contributor

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    You solution is correct.
    I do have one question: "why convert to degrees"?
    Radians are mathematical, not degrees. (My opinion)
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  3. #3
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    Good point. Honestly, I converted radian to degrees for no other reason than out of habit. I think I will write my answer in both radians and degrees. Thanks for your help!
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