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Math Help - Let f(x)=2x^2-4x+5

  1. #1
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    Question Let f(x)=2x^2-4x+5

    Let f(x)=2x^2 -4x+5.Suppose that F is an antiderivative of f such that
    F(1)=10.Find F(x).






    I think the anti derivative is as follows:

    F=2∫x^2 dx -4∫x dx + 5∫1 dx
    F=2.x^3/3-4.x^2/2+5.x+c

    But when I plug in 1 in the F i.e F(1) ...I do not get 10 as given in the problem.Can somebody pls help me?
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  2. #2
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    You must make c the number that makes that true. Plug in 1 for x, 10 for y then solve for c.
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  3. #3
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    Quote Originally Posted by Jameson View Post
    You must make c the number that makes that true. Plug in 1 for x, 10 for y then solve for c.
    Yes.

    So it will look like F(1)=10=2(1)^3/3 - 2(1)^2 +5(1) + c

    c= (whatever you get. solve algebraically)

    Rewrite F(x) with the correct value of c.
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