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Math Help - Evaluate using scientific notation.

  1. #1
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    Evaluate using scientific notation.

    I havent taken math for years so please help me out. The problem is:

    Using scientific notation, evaluate:


    (4 x 10^8)^3 divided by (5 x10^-6)^2

    Do I just convert this to 40 x 10^11 divided by 50 x 10^-4?

    If so..

    then I divide 40 by 50, which is .8

    So we got .8 x 10^7 as the answer.

    Am I doing this right? thanks.


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  2. #2
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    Quote Originally Posted by hansbethe View Post
    I havent taken math for years so please help me out. The problem is:

    Using scientific notation, evaluate:


    (4 x 10^8)^3 divided by (5 x10^-6)^2

    Do I just convert this to 40 x 10^11 divided by 50 x 10^-4?

    If so..

    then I divide 40 by 50, which is .8

    So we got .8 x 10^7 as the answer.

    Am I doing this right? thanks.


    \frac{(4\cdot 10^8)^3}{(5\cdot 10^{-6})^2}

     = \frac{4^3\cdot (10^8)^3}{5^2\cdot (10^{-6})^2}

     = \frac{64\cdot 10^{24}}{25 \cdot 10^{-12}}

     = \frac{64}{25}\cdot 10^{24 - (-12)}

     = \frac{64}{25}\cdot 10^{36}

     = \left(\frac{8}{5}\right)^2\cdot (10^{18})^2

     = \left(\frac{8}{5}\cdot 10^{18}\right)^2.
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  3. #3
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    Start with a refresher on exponent rules:
    Exponents: Basic Rules
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  4. #4
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    damn. lol. I was way off. thanks. what threw me off was the exponents outside the parentheses. I didnt know what to do with them. im gonna practice a couple more tomorrow. thanks a lot.
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  5. #5
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    Quote Originally Posted by Wilmer View Post
    Start with a refresher on exponent rules:
    Exponents: Basic Rules
    thanks i have a lot of those sites bookmarked. actually I already have that one bookmarked. I can do the simpler ones like 4.2 x 10^6 / 2 x 10^2 = 2.1 x 10^4

    I just didnt do one or learn to do one with parentheses.
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