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  1. #1
    Join Date
    Feb 2004
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    In this formula b = 6

    a = (2 x 20^4) / b^6
    So the answer is 6.8587

    If I already knew that a = 6.8587, and b was the unknown, how would I solve that problem so that the answer to b didn't come out in exponential form. I mean, so that the answer would come out as "6" instead of something to the something power?

    If it did come out as something to the something power, how would I convert that to a regular number?




  2. #2
    Join Date
    Mar 2004
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    SE Michigan
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    Holy cow...your asking me to remember my pre calculus days. When your trying to solve to that power things get tuff. Well, I will tell you right now Im not going to do it!





































    Im glad thats over.
    To put the world in order, we must first put the nation in order; to put the nation in order, we must put the family in order; to put the family in order, we must cultivate our personal life; and to cultivate our personal life, we must first set our hearts right.
    -- Confucius

  3. #3
    Join Date
    Sep 2001
    Location
    East Stroudsburg, PA
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    13,215
    Mid-

    You are going to sprain your brain if you keep this up.

  4. #4
    midhvac,

    Do the basic algebra and up end up with:

    b=(2x20^4/a)all raised to the 1/6

    You need a scientific calculator to get what b is. That is, 46656.07 ^1/6

    plug in all the numbers and the answer is 6.

    Is this what you were asking?

  5. #5
    Join Date
    Apr 2002
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    Dallas, TX
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    2,987
    Originally posted by midhvac
    In this formula b = 6

    a = (2 x 20^4) / b^6
    So the answer is 6.8587

    Perhaps some number theory may be appropriate here.

    'a' in this example is equal to exactly 320,000 / 46,656 or approximately 6.85871056241426611796982167352538 (using Microsoft calculator )

    'a' is considered a 'rational' number because it can be wriiten as a fraction, i.e., x / y where x and y are integers.

    Originally posted by midhvac

    If I already knew that a = 6.8587, and b was the unknown, how would I solve that problem so that the answer to b didn't come out in exponential form. I mean, so that the answer would come out as "6" instead of something to the something power?

    Ok, lets assume 'a' = 7, what is 'b'?

    b = (320,000 / 7)^(1/6)

    where 'b' is approximately 5.979643919487405903197485402773 (again using Microsoft calculator)

    In this case, 'b' is an irrational number. There is no fraction, x / y, that can define 'b' where x and y are integers. Think about it! No integer numbers whatsoever. Raising this expression to the 1/6th power causes this to occur.

    Mmmmm... so does this help?

  6. #6
    Join Date
    Feb 2004
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    Midwest
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    You guys rock! Thanks! I've got a scientific calculator and the 1/6 power works.

  7. #7
    Join Date
    Feb 2004
    Location
    Midwest
    Posts
    9,937
    Originally posted by condenseddave
    Mid-

    You are going to sprain your brain if you keep this up.
    Nah, I put an elastic support around my head, just in case.

  8. #8
    Join Date
    Feb 2004
    Location
    Midwest
    Posts
    9,937
    Hey! Wait a minute! Why are we using 1/6? Is it because the answer to b is 6? So I have to know the answer before I can work the problem?

  9. #9
    Join Date
    Apr 2002
    Location
    Dallas, TX
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    2,987
    Originally posted by midhvac
    Originally posted by condenseddave
    Mid-

    You are going to sprain your brain if you keep this up.
    Nah, I put an elastic support around my head, just in case.
    Let's put that elastic support to work...

    Using your calculator, solve the following:

    x^3 = x * x * x = -27

    or x = (-27)^(1/3)

    A little figuring will show that 'x' must equal -3, i.e., -3 * -3 * -3 = -27

    Why does the calculator fail to figure this out?




  10. #10
    Join Date
    Apr 2002
    Location
    Dallas, TX
    Posts
    2,987
    Originally posted by midhvac
    Hey! Wait a minute! Why are we using 1/6? Is it because the answer to b is 6? So I have to know the answer before I can work the problem?
    Nope. Using apropriate math:

    a = (2 x 20^4) / b^6

    a = 320,000 / b^6

    b^6 = 320,000 / a

    (b^6)^(1/6) = (320,000 / a)^(1/6)

    b = (320,000 / a)^(1/6)

  11. #11
    Join Date
    Nov 2004
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    Jonesboro, Arkansas
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    I think I am going into another field. I will never figure this stuff out!!!

  12. #12
    Join Date
    Mar 2003
    Location
    Cincinnati
    Posts
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    You big bunch of math nerds.

  13. #13
    Join Date
    Jan 2003
    Location
    SE Pa
    Posts
    830
    Originally posted by mattm
    You big bunch of math nerds.
    Yea , bet they got pocket protectors too>)

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