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Thread: What would these functions look like?

  1. #1
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    What would these functions look like?

    $\displaystyle y=sin6x$
    and
    $\displaystyle y=sin1/4x$

    In other words what might the zeroes be?
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  2. #2
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    Quote Originally Posted by crosser43 View Post
    $\displaystyle y=sin6x$
    and
    $\displaystyle y=sin1/4x$

    In other words what might the zeroes be?
    As masters wrote in this thread (http://www.mathhelpforum.com/math-he...lp-answer.html) the b is important. For the 1st one, b = 6, and for the 2nd one, b = 1/4.
    (BTW, your 2nd one in ambiguous. Some people may think that you mean $\displaystyle y = \sin \frac{1}{4x}$ instead of $\displaystyle y = \sin \frac{1}{4}x$.)

    You have to remember the zeros for y = sin x, which is
    $\displaystyle 0,\; \pi,\; 2\pi,\; 3\pi,...$;
    in other words, multiples of $\displaystyle \pi$.

    So to find the zeros of y = sin bx, divide the zeros I listed above by b. For y = sin 6x, the zeros are
    $\displaystyle 0,\; \frac{\pi}{6}\; \frac{\pi}{3}\; \frac{\pi}{2},...$.

    I'll let you try the other one.


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  3. #3
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    Quote Originally Posted by crosser43 View Post
    $\displaystyle y=sin6x$
    and
    $\displaystyle y=sin1/4x$

    In other words what might the zeroes be?
    Let $\displaystyle u = 6x$ . So now we have $\displaystyle y=\sin{u}$ . For which values of $\displaystyle u$ does $\displaystyle y=\sin{u} = 0$ ?

    Now use this and the fact that $\displaystyle x = \frac{u}{6}$ to find out the zeroes to $\displaystyle y=\sin{6x}$


    EDIT: tooo slow
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