Results 1 to 5 of 5

Math Help - Rearranging formulae

  1. #1
    Newbie
    Joined
    Jun 2008
    Posts
    16

    Rearranging formulae

    I need to know how to do the following examples of theory questions relating to rearranging formula:
    1. a/p ln (b-2T) = P, find T
    2. T= RC/t log (Vt/Vo) ,change to Vt
    3. 5(^3x+2) = 3(^2-x), change to x
    Any help would be great, thanks
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor alexmahone's Avatar
    Joined
    Oct 2008
    Posts
    1,074
    Thanks
    7
    1. \frac{a}{p} ln (b-2T) = P
    ln (b-2T)=\frac{Pp}{a}
    (b-2T)=e^\frac{Pp}{a}
    2T=b-e^\frac{Pp}{a}
    T=\frac{b-e^\frac{Pp}{a}}{2}

    2. T= \frac{RC}{t} log \frac{Vt}{Vo}
    log \frac{Vt}{Vo}=\frac{Tt}{RC}
    \frac{Vt}{Vo}=e^\frac{Tt}{RC}
    Vt=Voe^\frac{Tt}{RC}
    Last edited by alexmahone; June 1st 2009 at 06:14 AM.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Jun 2008
    Posts
    16
    thanks for that Alex, I had the right method just was getting confused. I dont even know where to start with the third one.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Newbie Singaporean's Avatar
    Joined
    May 2009
    From
    Singapore
    Posts
    19
    5^{3x+2} = 3^{2-x}

    3^{\frac{log 3}{log 5}(3x+2)}=3^{2-x}

    Then, {\frac{log 3}{log 5}(3x+2)}={2-x}

    Er, plausible? not really sure, just a suggestion
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Newbie
    Joined
    Jun 2008
    Posts
    16
    For that last one, this is what I came up with...

    5(^3x+2) = 3(^2-x), change to x

    ln5 (^3x+2) = ln 3(^2-x)
    (3x+12) ln5 = (2-x) ln3 3xln5= (-2) -(2-x) ln3
    3x+2 = (2-x)ln3/ ln5 3x ln5 = -x ln3

    3x = -x ln3/ln5

    Don't know if that is correct.I am also finding these difficult...

    ln (y + 5) = 3.1, solve for Y

    4 (^x+1) = 6^0.5x, solve for x

    I= Imax (1 -e^ -30t/0.01), find T

    again, any help would be appreciated
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 4
    Last Post: July 5th 2010, 07:20 AM
  2. Rearranging more formulae
    Posted in the Algebra Forum
    Replies: 1
    Last Post: April 15th 2010, 07:44 AM
  3. rearranging formulae with fractions
    Posted in the Algebra Forum
    Replies: 3
    Last Post: October 14th 2009, 12:33 PM
  4. Rearranging Formulae
    Posted in the Algebra Forum
    Replies: 2
    Last Post: November 8th 2008, 11:47 AM
  5. Urgent help with rearranging formulae
    Posted in the Algebra Forum
    Replies: 4
    Last Post: March 31st 2008, 02:22 PM

Search Tags


/mathhelpforum @mathhelpforum