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Math Help - y=2sin3x Reflection?

  1. #1
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    y=2sin3x Reflection?

    Help is greatly appreciated. Thank you in advance.

    The graph of  y=2sin 3x is reflected in the x-axis.

    a) Sketch a graph of one period of the original curve.

    b) Sketch a graph of the curve after the reflection.

    c) Write an equation for the new curve.
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  2. #2
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    Quote Originally Posted by ThaBeretta View Post
    Help is greatly appreciated. Thank you in advance.

    The graph of  y=2sin 3x is reflected in the x-axis.

    a) Sketch a graph of one period of the original curve.

    b) Sketch a graph of the curve after the reflection.

    c) Write an equation for the new curve.

     y=2sin 3x is the same as  y=sin(x) with the amplitude doubling and the period being one third the distance along the x-axis

    The reflection is the graph redrawn around the same central point the x-axis but flipped upside down. These things are really hard to explain in such a forum, it would be alot easier with pen and paper!

    The equation is:  y=-2sin 3x
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  3. #3
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    I kind of understand what you're saying. Is there any way you'd be able to sketch one or both graphs and scan them onto the computer? I know it's a bit much to ask for, but this is really hard to explain and understand over text.
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  4. #4
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    I have attached an excel file
    Attached Files Attached Files
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  5. #5
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    That's awesome! Now I see what you mean by the wave flipped upside down. Thanks again for your help and patience!
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  6. #6
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    I'm sorry, but one last thing. I see how the graphs are created, but how would I sketch them? The problem wants only one period. Could I just graph them from 0 to 2pi? If so, how would I fit three sin curves in?
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  7. #7
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    Quote Originally Posted by ThaBeretta View Post
    I'm sorry, but one last thing. I see how the graphs are created, but how would I sketch them? The problem wants only one period. Could I just graph them from 0 to 2pi? If so, how would I fit three sin curves in?
    You are correct in saying three curves would fit between 0 and 2pi.

    I would draw an x-axis from 0 to 2 pi and cut it evenly into 3. Then draw the graphs into these intervals. Each repetition should end at pi/3,2pi/3 and 2pi.

    Make sense?!
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  8. #8
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    Yeah, I think I got it. Thanks for all of your help and time.
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