Results 1 to 6 of 6

Math Help - help with rearranging equation please

  1. #1
    Newbie
    Joined
    May 2009
    Posts
    17

    help with rearranging equation please

    hello there struggling to get this right in my head

    i have an equation

    Fr=1/2Pi sqrtLC and need to make Lc the subject

    it is written as Fr equals 1 over 2pi times sqroot of LC (ie both 2pi and sqrtLc both divided by 1)

    i got Lc2=1/2pi Fr not convinced im right though

    any help appreciated

    ian
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    Jun 2009
    Posts
    220
    Thanks
    1
    Quote Originally Posted by tommoturbo View Post
    hello there struggling to get this right in my head

    i have an equation

    Fr=1/2Pi sqrtLC and need to make Lc the subject

    it is written as Fr equals 1 over 2pi times sqroot of LC (ie both 2pi and sqrtLc both divided by 1)

    i got Lc2=1/2pi Fr not convinced im right though

    any help appreciated

    ian

    I'm sorry but this is really poorly presented, try using parenthesis to make your expressions clearer. (better yet learn Latex)

    Is your original equation: Fr = \frac{1}{2 \pi \sqrt{LC}} ?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    May 2009
    Posts
    17
    Yes thats exactlly the equation (sorry im no good at that sort of stuff)
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Junior Member
    Joined
    Jul 2009
    Posts
    28

    Smile

    Fr = \frac{1}{2 \pi \sqrt{LC}}

    Multiply both sides by \sqrt{LC} to give
    Fr\sqrt{LC} = \frac{1}{2 \pi }

    Divide both sides by Fr to give
    \sqrt{LC} = \frac{1}{2 \pi Fr}

    Now square both sides to give
    LC = \left(\frac{1}{2 \pi Fr}\right)^2
    so
    LC= \frac{1^2}{\left(2 \pi Fr\right)^2}
    so
    LC= \frac{1}{4 \pi^2 \left(Fr\right)^2}

    Is that what you were after?

    Si
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Newbie
    Joined
    May 2009
    Posts
    17
    wow thanks for the quick response, thats exactly what i am after, i was almost getting it but forgetting to multiply 2pi to get 4pi.


    Much appreciated

    thanks Ian
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Junior Member
    Joined
    Jul 2009
    Posts
    28
    No problem.

    Just remember the golden rule:
    (ab)^2=a^2b^2

    But (a+b)^2\neq a^2+b^2!!!!

    In fact (a+b)^2= a^2+2ab+b^2

    Si
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. rearranging an equation
    Posted in the Algebra Forum
    Replies: 2
    Last Post: August 14th 2013, 09:42 AM
  2. Rearranging an equation.
    Posted in the Algebra Forum
    Replies: 9
    Last Post: February 20th 2010, 09:46 PM
  3. Rearranging Equation
    Posted in the Algebra Forum
    Replies: 1
    Last Post: October 9th 2009, 02:54 PM
  4. Rearranging an equation help please
    Posted in the Algebra Forum
    Replies: 3
    Last Post: August 12th 2009, 07:20 AM
  5. just rearranging an equation, is it possible?
    Posted in the Algebra Forum
    Replies: 1
    Last Post: July 21st 2009, 07:12 AM

Search Tags


/mathhelpforum @mathhelpforum