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How to define acos in relation to cos?

  1. Nov 2, 2011 #1

    Does anyone know how to calculate the formula for acos in relation to cos?

    We know that cos (∏/3) = 0.5
    and acos(0.5) = ∏/3

    However, I assumed I could calculate acos(x) in relation to cos(x) as: 1/cos(x).
    Well, I assumed wrong :(

    Is there any way to do this?

  2. jcsd
  3. Nov 2, 2011 #2
    "Is there any way to do this?"

    Unfortunately not. However, you can express acos as a function of any of the other inverse trig functions.
  4. Nov 2, 2011 #3
    Although you probably have way more experience than me in mathematics, I find your answer hard to believe...

    Since acos is an inverse function of cos, they must be related in some way? If not, you just turned my whole mathematical beliefs upside down!
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