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Homework Help: Proof: (a^c)^d = a^(cd)

  1. Feb 9, 2012 #1
    1. The problem statement, all variables and given/known data

    The problem is in the title: Prove (a^c)^d) = a^(cd)

    2. Relevant equations

    N is the set of natural numbers.

    (ab)^n = (a^n)(b^n)
    a^(p+n) = (a^p)*(a^n)
    ((a^p)(a^n)) * a = (a^p)(a^(n+1))

    3. The attempt at a solution

    c = p-q; d = j-k; p,q,j,kεN (by definition of integers)



    ((a^(p+(-q)))^j)/((a^(p+ (-q)))^k)

    ((a^p)(a^(-q)))^j/((a^p)(a^(-q)))^k or (((a^p)/(a^q))^j)/(((a^p)/(a^q))^k)

    I have no idea where to go from here. I've spent two hours on this and I've finished nearly all my other proofs on this assignment...This one is killing me though, and I have other work I need to get to at some point. Could anyone please give me a tip in the right direction? I feel like I have it all wrong.
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Feb 9, 2012 #2


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    Science Advisor
    Homework Helper

    Welcome to PF!

    Hi Llamas! Welcome to PF! :smile:

    What are c and d, are they all natural (whole) numbers?

    if so, just write ac = a times ac-1 :wink:
  4. Feb 11, 2012 #3
    Re: Welcome to PF!

    Thank you tiny-tim, the advice helped me finish the proof. Sorry I didn't respond until now, had other work as well.
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