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Math Help - Indices and Logarithms Help

  1. #1
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    Indices and Logarithms Help

    hopefully can help explain these, they the last question i need to do but its mainly the reason i need
    A) 2x-2 Equivalent expression 2/X-2
    1/2x2 Equivalent expression x -2
    my problem is the reasoning for these

    B) Log2(8) = 4 False My Answer - Log2(16) = 4
    Log16(4)= 1/4 False My Answer - Log16(2) = 1/4
    Log2(1/8)= -3 True

    and again here its the reasoning but for my answers

    i hope u can understand that i get it but for the reasoning i just go blank :S
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  2. #2
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    Quote Originally Posted by Ian360 View Post
    hopefully can help explain these, they the last question i need to do but its mainly the reason i need
    A) 2x-2 Equivalent expression 2/X-2
    1/2x2 Equivalent expression x -2
    my problem is the reasoning for these

    B) Log2(8) = 4 False My Answer - Log2(16) = 4
    Log16(4)= 1/4 False My Answer - Log16(2) = 1/4
    Log2(1/8)= -3 True

    and again here its the reasoning but for my answers

    i hope u can understand that i get it but for the reasoning i just go blank :S
    I don't see any reason for (A).

    The reasoning for (B) is this:

    \log_ax=n means a^n=x
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  3. #3
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    Quote Originally Posted by masters View Post
    I don't see any reason for (A).

    The reasoning for (B) is this:

    \log_ax=n means a^n=x
    thanks for the help on (B) cant believe how simple it is now for them

    but now im stuck on the indices how can you tell if they are similar and which give products of 1..2...3 etc etc
    this is what im having to do i need to match 2 with the equivant equation and also match 2 that give a product of 1...this is confusing me as in my notebook its tell me that indices are a3 + d2 something like that
    Last edited by Ian360; December 4th 2008 at 04:05 PM. Reason: to make my problem clearer
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  4. #4
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    Quote Originally Posted by Ian360 View Post
    thanks for the help on (B) cant believe how simple it is now for them

    but now im stuck on the indices how can you tell if they are similar and which give products of 1..2...3 etc etc
    this is what im having to do i need to match 2 with the equivant equation and also match 2 that give a product of 1...this is confusing me as in my notebook its tell me that indices are a3 + d2 something like that
    I'm still not sure exactly what you're trying to do, but as far as finding products that equal 1, 2, etc.

    Rewriting the rows:

    \frac{1}{2x^2} \ \ \ \ \frac{1}{2\sqrt{x}} \ \ \ \ \frac{2}{x} \ \ \ \ \frac{2}{\sqrt{x}} \ \ \ \ \frac{1}{2x}

    2\sqrt{x} \ \ \ \ \frac{2}{x^2} \ \ \ \ \frac{1}{2\sqrt{x}} \ \ \ \ \frac{1}{2x^2} \ \ \ \ 2x^2
    ----------------------------------------------------------------------
    \frac{1}{2x^2}\cdot 2x^2 = 1

    2\sqrt{x} \cdot \frac{1}{2\sqrt{x}}=1

    \frac{2}{x^2}\cdot 2x^2=4

    Is this what you're talking about? If so, try some products and see what happens.
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  5. #5
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    Quote Originally Posted by masters View Post


    I'm still not sure exactly what you're trying to do, but as far as finding products that equal 1, 2, etc.

    Rewriting the rows:

    \frac{1}{2x^2} \ \ \ \ \frac{1}{2\sqrt{x}} \ \ \ \ \frac{2}{x} \ \ \ \ \frac{2}{\sqrt{x}} \ \ \ \ \frac{1}{2x}

    2\sqrt{x} \ \ \ \ \frac{2}{x^2} \ \ \ \ \frac{1}{2\sqrt{x}} \ \ \ \ \frac{1}{2x^2} \ \ \ \ 2x^2
    ----------------------------------------------------------------------
    \frac{1}{2x^2}\cdot 2x^2 = 1

    2\sqrt{x} \cdot \frac{1}{2\sqrt{x}}=1

    \frac{2}{x^2}\cdot 2x^2=4

    Is this what you're talking about? If so, try some products and see what happens.

    thats what i was talking about thanks for the help i understand how it works now
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