Results 1 to 2 of 2

Math Help - Help with simplifying fraction with a negative exponent.Unsure of final result steps

  1. #1
    Newbie
    Joined
    Nov 2009
    Posts
    15

    Help with simplifying fraction with a negative exponent.Unsure of final result steps

    Not sure what happened with the R^-0.67 in getting to the final expression for MP. I understand substituting Gw back into the formula but how does it become (Gw/R). And also the .83 constant becomes .33?

    I would have just brought the R^ -0.67 to the denominator to get a positive exponent.

    Thank you!
    Attached Thumbnails Attached Thumbnails Help with simplifying fraction with a negative exponent.Unsure of final result steps-mathq.bmp  
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member Quacky's Avatar
    Joined
    Nov 2009
    From
    Windsor, South-East England
    Posts
    901

    Re: Help with simplifying fraction with a negative exponent.Unsure of final result st

    We have:

    MP^w_r=\frac{0.83A^{0.67}}{R^{0.67}}

    We want to substitute in G_w=2.5A^{0.67}R^{0.33}

    But two things hinder us:
    -The uneven powers of R
    -The unequal constants.

    Some quick division tells us that 0.83=2.5(0.332)

    So we have:

    MP^w_r=\frac{0.83A^{0.67}}{R^{0.67}}

    MP^w_r=\frac{0.332(2.5)A^{0.67}}{R^{0.67}}

    There are two ways to view the next step:

    You could conceptualize it as multiplying through by \frac{R^{0.33}}{R^{0.33}} to give:

    MP^w_r=\frac{0.332(2.5)A^{0.67}R^{0.33}}{R^{0.67}R  ^{0.33}}

    MP^w_r=\frac{0.332(2.5)A^{0.67}R^{0.33}}{R^{1}}

    And then you can make the substitution.

    Or consider the fact that x^a\cdot{x^b}=x^{a+b}

    We need R^{0.33} in the numerator.
    We currently have R^{-0.67} in the numerator. You can then deduce that R^{0.33}R^{-1}=R^{-0.67} so we can rewrite R^{-0.67} as R^{0.33}R^{-1}

    Either way, we are left with:

    MP^w_r=\frac{0.332(2.5)A^{0.67}R^{0.33}}{R^{1}}

    And we want to substitute in:

    G_w=2.5A^{0.67}R^{0.33}

    Which we can now do, leaving:

    MP^w_r=\frac{0.332G_w}{R^{1}}
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 1
    Last Post: November 11th 2011, 03:31 PM
  2. Replies: 3
    Last Post: April 27th 2011, 04:53 PM
  3. Negative fraction with exponent?
    Posted in the Algebra Forum
    Replies: 4
    Last Post: January 28th 2011, 07:54 PM
  4. Replies: 3
    Last Post: December 11th 2010, 01:04 AM
  5. Replies: 1
    Last Post: August 19th 2008, 08:41 AM

Search Tags


/mathhelpforum @mathhelpforum