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Math Help - simple function problem

  1. #1
    dla
    Guest

    simple function problem

    I have just started uni maths and never having done it before I'm having trouble with real simple things (I think)

    this is a question from the washington book

    one is this:

    f(T) = 10.0 + 0.10T + 0.001T^2

    t is temperature increases by 10 so f(T + 10)

    f(T + 10) = 10 + 0.10(T + 10) + 0.001(T + 10)^2
    = 10.0 + 0.10T + 1.0 + 0.001T^2 +0.02T + 0.1

    I get how the first half works out but the second bit in bold I have no idea how that is possible, as I said its probably very simple but I've been staring at it for ages and can't figure it out...

    Would really appreciate any help
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  2. #2
    MHF Contributor
    Joined
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    Quote Originally Posted by dla View Post

    f(T + 10) = 10 + 0.10(T + 10) + 0.001(T + 10)^2
    = 10.0 + 0.10T + 1.0 + 0.001T^2 +0.02T + 0.1

    I get how the first half works out but the second bit in bold I have no idea how that is possible, as I said its probably very simple but I've been staring at it for ages and can't figure it out...

    Would really appreciate any help
    . The book skipped one step.
    It should have shown that the (T +10)^2 is expanded to
    (T^2 +20T +100).

    The book can skip one step, two steps, etc., depending on how it assumes the reader can follow the solution.
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  3. #3
    Grand Panjandrum
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    Quote Originally Posted by dla View Post
    I have just started uni maths and never having done it before I'm having trouble with real simple things (I think)

    this is a question from the washington book

    one is this:

    f(T) = 10.0 + 0.10T + 0.001T^2

    t is temperature increases by 10 so f(T + 10)

    f(T + 10) = 10 + 0.10(T + 10) + 0.001(T + 10)^2
    = 10.0 + 0.10T + 1.0 + 0.001T^2 +0.02T + 0.1

    I get how the first half works out but the second bit in bold I have no idea how that is possible, as I said its probably very simple but I've been staring at it for ages and can't figure it out...

    Would really appreciate any help
    What you need to know is that:

    0.001(T + 10)^2=.001(T + 10)(T + 10)

    Now we multiply out the brackets:


    0.001(T + 10)^2=0.001(T + 10)(T + 10)=0.001(T^2+20T+100)

    and now multiply through by the 0.001:

    0.001(T + 10)^2=0.001(T + 10)(T + 10)=0.001(T^2+20T+100)=0.001T^2+0.02T+0.1


    RonL
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