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Math Help - f(4)=?

  1. #1
    Raj
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    f(4)=?

    Consider the function f(x) whose second derivative is f(x)=2x+9sin(x). If f(0)=4 and f(0)=4, what is f(4)?

    I don't know what i'm supposed to know given f(0) and f'(0). Help please.
    Is it giving me the C value when i take the anti derivative? =/
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    MHF Contributor Drexel28's Avatar
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    Quote Originally Posted by Raj View Post
    Consider the function f(x) whose second derivative is f(x)=2x+9sin(x). If f(0)=4 and f(0)=4, what is f(4)?

    I don't know what i'm supposed to know given f(0) and f'(0). Help please.
    Is it giving me the C value when i take the anti derivative? =/
    When you take the indefinite integral of your function, in each case, you will be left with an unknowns constant. Use the given information to determine the constant.
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    Quote Originally Posted by Raj View Post
    Consider the function f(x) whose second derivative is f(x)=2x+9sin(x). If f(0)=4 and f(0)=4, what is f(4)?

    I don't know what i'm supposed to know given f(0) and f'(0). Help please.

    f'(x)=\int f''(x)dx\,,\,f(x)=\int f'(x)dx...but there is that annoying integration constant every time, so the given data helps you to find what exactly are those constants and thus know completely the function.

    Tonio
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