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Math Help - Rearranging my perfect formula

  1. #1
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    Rearranging my perfect formula

    Yes I am a student, and a newby, please be gentle with me . I am looking for help rearranging this formula I devised for a project (yes it is correct). Manipulation is not my thing so if anyone can crack it I would appreciate time and workings, I am sure this is easy for most people with an interest in math / physics.

    Here goes- (((F/R)-m)/6)R=M, I need to make R the subject but I cannot figure out how to get the middle R out.

    Happy figuring

    Cheers
    T
    Last edited by horcigirl; February 25th 2009 at 10:44 PM. Reason: Forgot to sign name
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  2. #2
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    Quote Originally Posted by horcigirl View Post
    ... Manipulation is not my thing ...

    Here goes- (((F/R)-m)/6)R=M, I need to make R the subject but I cannot figure out how to get the middle R out.

    ...
    I'm going to show you what to do and maybe rearranging will become your favourite hobby:

    \dfrac{\frac FR - m}6 \cdot R = M

    \left(\frac FR - m \right) \cdot R =6 M

    F - mR =6 M

     - mR =6 M - F

     R =\dfrac{6 M - F}{-m} = \dfrac{F-6M}m
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  3. #3
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    Thats great and it works but!!

    Awesome, That is sooo cool , I have checked it and it works but I am confused about some of your workings. Yes I am fascinated by how manipulation works but get confused by some issues. I had the right idea but I still cannot understand what happened to the middle R as it has just disappeared, I thought it would affect the other R to become R squared or 2R somehow. Why has it just been dropped?

    I appreciate your help as I get very frustrated with this sort of thing, especially when I have been so clever with creating an effective formula lol.
    Cheers
    T
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  4. #4
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    Quote Originally Posted by horcigirl View Post
    I had the right idea but I still cannot understand what happened to the middle R as it has just disappeared, I thought it would affect the other R to become R squared or 2R somehow. Why has it just been dropped?
    It has not disappeared, it has been distributed

    (a+b) \cdot c = a \cdot c + b \cdot c

    \left(\frac FR - m \right) \cdot R =6 M

    \frac FR \cdot R - m \cdot R =6 M

    F - mR =6 M
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  5. #5
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    Smile Understood

    Thanks for the help. Its like multipliyng 1/2 by 2. I thought in this case both numerator and denominator would have had to be multiplied, still leaving FR. However I now understand what has been done.

    Thanks to both advisors. My confidence is renewed. I see an A+ in sight lol.

    Cheers
    T
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