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Combining equations help

  1. May 27, 2012 #1
    I am reading this in a book and am having trouble understanding this.

    Can someone explain the step by step the process in changing equation A into equation B?

    Mrc= 2/3Pcb x b x 1/2d1 x 3/4d1

    = 1/4Pcb x b x (d1)2

    Many Thanks
  2. jcsd
  3. May 27, 2012 #2

    It is almost impossible to understand what you wrote (for me it is completely impossible). Please do learn how to use LaTeX within this site to write mathematics.

  4. May 27, 2012 #3

    Stephen Tashi

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    Science Advisor

  5. May 27, 2012 #4
    It made perfect sense,

    Remember that multiplication, does not require any distribution, that is, some students write

    A(BC)=(AB)(AC). This is wrong. They are thinking of A(B+C)=AB+AC.

    So multiplication only needs to happen once.

    you have a copy of 2/3, 1/2 and 3/4. Take the first two 2/3 and 1/2, their product is 1/3.

    Then 1/3 times 3/4 is 1/4. They also have two copies of d1, so that is (d1)^2.

    I'm assumig by d1, you meant d[itex]_1[/itex]
  6. May 29, 2012 #5
    Thanks Algebrat,

    You have explained it very clearly, and now I understand.
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