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New interest in Physics.

  1. Mar 27, 2008 #1
    Hey everyone,

    I have recently developed a strong interest in physics. To the point where I am changing my major from computer science to computational physics. Anyway, I am having a problem understanding a formula in a book I have on relativity. The problem is:
    90[tex]\circ[/tex] = arcsec(300/1000). Now I know some Trig. but I haven't done it in awhile and don't remember arcsec at all. Can anyone explain to me why that problem equals 90 degrees.

  2. jcsd
  3. Mar 27, 2008 #2
    secx is equal to 1/cosx. arcsecx would then be equal to the angle that causes sec to equal x.

    However, because cosx is always <= 1, then 1/cosx cannot be less than 1. Therefore, if 300/1000=3/10, arcsec(300/1000) shouldn't exist.
  4. Mar 27, 2008 #3
    That is was the conclusion I was coming up with also. Maybe I am misunderstanding the problem.
    This is the exact problem from the book:http://books.google.com/books?id=fz...q9xmXR&sig=ZM6PZ9v6XRaqWad6pn9UxlufThQ&hl=en"
    Last edited by a moderator: Apr 23, 2017
  5. Mar 27, 2008 #4
  6. Mar 27, 2008 #5


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  7. Mar 28, 2008 #6
    The formula should say arccotangent, not arcsecant.
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