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Math Help - arcsec proplem pls

  1. #1
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    arcsec proplem pls

    Evaluate arcsec sec -9pie/7

    pleas explain the steps thanks
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  2. #2
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    Quote Originally Posted by kevintrung View Post
    Evaluate arcsec sec -9pie/7

    pleas explain the steps thanks
    you need to know that the range of the inverse secant function is ...

    \left[0,\frac{\pi}{2}\right) \cup \left(\frac{\pi}{2} , \pi\right]<br />

    get an angle co-terminal with \theta = -\frac{9\pi}{7} that is in the range of the inverse secant function ...

    \sec\left(-\frac{9\pi}{7}\right) = \sec\left(\frac{5\pi}{7}\right)

    arcsec\left[\sec\left(\frac{5\pi}{7}\right)\right] = \frac{5\pi}{7}
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  3. #3
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    Quote Originally Posted by skeeter View Post
    you need to know that the range of the inverse secant function is ...

    \left[0,\frac{\pi}{2}\right) \cup \left(\frac{\pi}{2} , \pi\right]<br />

    get an angle co-terminal with \theta = -\frac{9\pi}{7} that is in the range of the inverse secant function ...

    \sec\left(-\frac{9\pi}{7}\right) = \sec\left(\frac{5\pi}{7}\right)

    arcsec\left[\sec\left(\frac{5\pi}{7}\right)\right] = \frac{5\pi}{7}
    thanks i think i got it now, my professor is so rush in this stuff
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