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Math Help - Trig Proof Issue..

  1. #1
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    Trig Proof Issue..

    I am currently smashing my face into my desk from frustration of this trig proof. People have told me it's easy, but for whatever reason, I can not for the life of me figure out how to do it. The problem is:

    (sin³x + cos³x) / (sinx + cosx) = (1 - sinx cosx)

    Any help with this would be greatly apperciated..

    Thanks in advance!
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  2. #2
    Behold, the power of SARDINES!
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    Quote Originally Posted by Ramar View Post
    I am currently smashing my face into my desk from frustration of this trig proof. People have told me it's easy, but for whatever reason, I can not for the life of me figure out how to do it. The problem is:

    (sin³x + cos³x) / (sinx + cosx) = (1 - sinx cosx)

    Any help with this would be greatly apperciated..

    Thanks in advance!
    Do you remember the formula for factoring the sum of cubes.

    A^3+B^3=(A+B)(A^2-AB+B^2)

    This should finish the proof for you.

    Good luck.
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  3. #3
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    Holy cow. I can't believe I missed that. lol thanks for the help and the quick response. =)
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