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    Could someone help me solve this equation for C..
    .i know its easy but i seem to be getting a possible wrong answer. Im creating a function and i getting a more logical answer when i use another method to solve it but when just solving this equation the answers don't match up with my others. I just a bit skeptical with these things...

    Its a practice IA our math teacher has given us


    -1.1= 2.68Sin (-1.5 (7 - C)) + 0.28
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    PS Helper
    Try putting everything to one side so you end up with a number = sin(theta). Then you should be able to work out what theta should be. Would you know where to go from there?
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    -1.1 - 0.28 = 2.68 \sin(-1.5(7-C))
    -1.38 = 2.68 sin(-1.5(7-c))
    \frac{-1.38}{2.68} = \sin(-1.5(7-c))

    Unparseable or potentially dangerous latex formula. Error 4: no dvi output from LaTeX. It is likely that your formula contains syntax errors or worse.
    \sin^{-1}{\frac{-1.38}{2.68} = -1.5(7-c)


    7 - \frac{\sin^{-1}(\frac{-1.38}{2.68})}{-1.5} = c


    Remember to keep calculator in radian mode:
    c=6.639
    =]

    btw, does this forum have latex support?
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    not how i did it but i got C=-0.011

    1) -1.1= 2.68Sin (0.363 (-1.5 - C)) + 0.28
    2) -1.1 – 0.28 = 2.68Sin (-0.545 – 0.363C)
    3) -1.38 = -1.389 - 2.68Sin(0.363C)
    4) -1.38 +1.389 = -0.952C
    5) 0.01 = -0.952C
    6) 0.01 ÷ -0.952 = C
    7) C ≈ -0.011
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    wait wait wait. line 1:

    it's 2.68 sin(-1.5(7-c))....

    i believe u did not expand correctly here =]
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    Its the holidays...why the hell are you working? chill...relax!!!!
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    (Original post by pHysiX)
    -1.1 - 0.28 = 2.68 sin(-1.5(7-C))
    -1.38 = 2.68 sin(-1.5(7-c))
    [-1.38/2.68] = sin(-1.5(7-c))

    sin^-1[-1.38/2.68] = -1.5(7-c)

    sin^-1[-1.38/2.68]
    7 - ------------------ = c
    -1.5

    Remember to keep calculator in radian mode:
    c=6.639
    =]

    btw, does this forum have latex support?
    http://www.thestudentroom.co.uk/wiki/LaTex

    :yep:
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    hahaha i'm australian. only got 3 more mths until my final exam >.<
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    (Original post by Grunx)
    not how i did it but i got C=-0.011

    1) -1.1= 2.68Sin (0.363 (-1.5 - C)) + 0.28
    2) -1.1 – 0.28 = 2.68Sin (-0.545 – 0.363C)
    3) -1.38 = -1.389 - 2.68Sin(0.363C)
    4) -1.38 +1.389 = -0.952C
    5) 0.01 = -0.952C
    6) 0.01 ÷ -0.952 = C
    7) C ≈ -0.011
    I'm sturggling to follow this but on line 3 it looks like youve decided to just split the sin(somthing-somthing) to get a number and the sin(C).

    You can't do this, it doesn't work. You have to treat everything in the sin() as one entity until the you get rid of the sin()
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    hmmm if the question is as in the first post, then grunx has already made a mistake in the first line.

    however, in terms of methodology, i agree with the muon. if you want to split the sine, use the formula:
    \sin(A+B) = \sin(A)\cos(B)+\sin(B)\cos(A)
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    Sorry ive posted the question Wrong,,,

    1) -1.1= 2.68Sin (0.363 (-1.5 - C)) + 0.28

    Thankyou for your help pHysiX ...Really appreciate youe help
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    I performed the same calculations as you have physix and came up with the same answer as i previously did even though it was incorrect.
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    1) -1.1= 2.68Sin (0.363 (-1.5 - C)) + 0.28
    2) -1.1 – 0.28 = 2.68Sin (-0.545 – 0.363C)
    3) -1.38 = -1.389 - 2.68Sin(0.363C)
    4) -1.38 +1.389 = -0.952C
    5) 0.01 = -0.952C
    6) 0.01 ÷ -0.952 = C
    7) C ≈ -0.01


    1) -1.1= 2.68Sin (0.363 (-1.5 - C)) + 0.28
    2) -1.1 – 0.28 = 2.68Sin (0.363 (-1.5 - C))
    3) -1.38 = 2.68Sin (0.363 (-1.5 - C))
    4) -0.515 = Sin (0.363 (-1.5 - C))
    5) Sin-1 (-0.515) = (0.363 (-1.5 - C))
    6) 1.5- ( (Sin-1 (-0.515))÷(0.363) ) =C
    7) C≈ -0.01
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    that's the answer i'm getting as well. u should be right =]
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    Thanks again mate =)
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    (Original post by Grunx)
    not how i did it but i got C=-0.011

    1) -1.1= 2.68Sin (0.363 (-1.5 - C)) + 0.28
    2) -1.1 – 0.28 = 2.68Sin (-0.545 – 0.363C)
    3) -1.38 = -1.389 - 2.68Sin(0.363C)
    4) -1.38 +1.389 = -0.952C
    5) 0.01 = -0.952C
    6) 0.01 ÷ -0.952 = C
    7) C ≈ -0.011
    Where has the 0.363 figure come from? I thought it was seven(7) !

    The above is not correct.
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    I typed in the wrong digits and thusly a false answer. Could u help me with the question in my other post titled "Another one of those"...thx Steve
 
 
 
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