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Math Help - The 6 Trigonometric values

  1. #1
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    Question The 6 Trigonometric values

    Find the 6 trigonometric values of theta= cos^-1 (3/7)

    Now I was thinking cos^-1 = (3/7) is equivalent to secant=3/7 right? Meaning cosine would be 7/3. I draw my triangle, and solve for the last side by using pythagorean theorem. When I have all three sides I can identify my remaining 4 trigonometric values. Is this right?
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  2. #2
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    Quote Originally Posted by fezz349 View Post
    Find the 6 trigonometric values of theta= cos^-1 (3/7)

    Now I was thinking cos^-1 = (3/7) is equivalent to secant=3/7 right? Meaning cosine would be 7/3. I draw my triangle, and solve for the last side by using pythagorean theorem. When I have all three sides I can identify my remaining 4 trigonometric values. Is this right?
    \theta = \cos^{-1}(x) is not a reciprocal function, it's the inverse cosine function.

    if \theta = \cos^{-1}\left(\frac{3}{7}\right) , then \cos{\theta} = \frac{3}{7}

    note that \theta in this case is restricted to quad I because the range of the inverse cosine function is [0,\pi]
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  3. #3
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    is not a reciprocal function, it's the inverse cosine function.

    if , then

    note that in this case is restricted to quad I because the range of the inverse cosine function is

    hmm... i don't remember learning that in class to be honest. i hope you don't mind me asking a couple questions to clear things up so I can better understand and work through this. What's the difference between a reciprocal function and an inverse function, and what about this inverse cosine function makes it so costheta=3/7 is equivalent to cos^-1(3/7). If you're speaking about an inverse in any situation doesn't that generay mean to opposite?
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    thanks a lot skeeter ^_^
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