Results 1 to 6 of 6

Math Help - V=B-q/k In(r-1): Make r the subject.

  1. #1
    Newbie
    Joined
    Oct 2010
    Posts
    4

    V=B-q/k In(r-1): Make r the subject.

    hi

    i have a equation which i dont know how to solve it, as i have never seen this equation before !!

    question

    given : V=B-q/k In(r-1)

    make r subject of the formula ?

    could you please explain what they want exactly

    thanks
    Last edited by mr fantastic; October 6th 2010 at 12:25 PM. Reason: Re-titled.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by manfred View Post
    hi

    i have a equation which i dont know how to solve it, as i have never seen this equation before !!

    question

    given : V=B-q/k In(r-1)

    make r subject of the formula ?

    could you please explain what they want exactly

    thanks
    They want you to solve for r in terms of the other pronumerals. I suggest that you first attempt to make ln(r-1) the subject.

    By the way, your expression is ambiguous. Is it meant to be V=B-q/[k In(r-1)] or V=[B-q/k] In(r-1) ....?? Or V=(B-q)/[k In(r-1)] or V=B-(q/[k In(r-1)]) etc. etc. Please use bracketes, or take the couple of minutes to learn how to use latex (click on the appropriate link in my signature).
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Oct 2010
    Posts
    4
    Quote Originally Posted by mr fantastic View Post
    They want you to solve for r in terms of the other pronumerals. I suggest that you first attempt to make ln(r-1) the subject.

    By the way, your expression is ambiguous. Is it meant to be V=B-q/[k In(r-1)] or V=[B-q/k] In(r-1) ....?? Or V=(B-q)/[k In(r-1)] or V=B-(q/[k In(r-1)]) etc. etc. Please use bracketes, or take the couple of minutes to learn how to use latex (click on the appropriate link in my signature).
    yes i meant V=[B-q/k] In(r-1)

    could you please show me the solutions to it then i can understand how and where its coming from in solving it please thanks
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor
    skeeter's Avatar
    Joined
    Jun 2008
    From
    North Texas
    Posts
    11,701
    Thanks
    454
    Quote Originally Posted by manfred View Post
    yes i meant V=[B-q/k] In(r-1)

    could you please show me the solutions to it then i can understand how and where its coming from in solving it please thanks
    \displaystyle V=\left(B - \frac{q}{k}\right) \cdot \ln(r-1)

    \displaystyle \frac{V}{B - \frac{q}{k}} = \ln(r-1)

    \displaystyle e^{\frac{V}{B - \frac{q}{k}}} = r - 1<br />

    \displaystyle 1 + e^{\frac{V}{B - \frac{q}{k}}} = r
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor

    Joined
    Apr 2005
    Posts
    15,725
    Thanks
    1478
    Quote Originally Posted by manfred View Post
    hi

    i have a equation which i dont know how to solve it, as i have never seen this equation before !!
    I hope you do NOT mean that the only equations you can solve are those that you have seen before!

    question

    given : V=B-q/k In(r-1)

    make r subject of the formula ?

    could you please explain what they want exactly

    thanks
    By the way, it is "ln" (small L) NOT "In", for natural logarithm.
    Follow Math Help Forum on Facebook and Google+

  6. #6
    MHF Contributor
    Joined
    Dec 2007
    From
    Ottawa, Canada
    Posts
    3,102
    Thanks
    68
    Quote Originally Posted by manfred View Post
    yes i meant V=[B-q/k] In(r-1)
    Well, make your life easier by making x = B - q/k; then:
    Ln(r - 1) = V / x
    r - 1 = e^(V / x)
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Make Y the subject
    Posted in the Algebra Forum
    Replies: 6
    Last Post: August 17th 2011, 06:30 PM
  2. [SOLVED] Make x the subject in each of the following...
    Posted in the Algebra Forum
    Replies: 3
    Last Post: December 12th 2010, 09:40 PM
  3. [SOLVED] Make x the subject
    Posted in the Algebra Forum
    Replies: 6
    Last Post: August 8th 2010, 07:54 AM
  4. Make t subject
    Posted in the Algebra Forum
    Replies: 30
    Last Post: December 8th 2009, 06:52 AM
  5. make L subject
    Posted in the Algebra Forum
    Replies: 3
    Last Post: November 29th 2009, 02:54 PM

Search Tags


/mathhelpforum @mathhelpforum