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Math Help - Definite integral solution

  1. #1
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    Definite integral solution

    Hi all,
    Can you tell me if i am correct?

    Evaluate "integral sign"- [(2x^3)+(3x^2)-(4x)+5).dx between limits 5(b) and 0(a).

    Integrating each term individually gives:

    ((x^4)/2)+(x^3)-(2x^2)+(5x).

    and as b=x=5 and a=x=0

    {f(b)-f(a)}

    [((5^4)/2)+(5^3)-(2(5)^2)+(5(5))]-[((0^4)/2)+(0^3)-(2(0)^2)+(5(0))]

    [312.5+125-50+25]-[0]

    =412.5

    thanks
    John
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  2. #2
    MHF Contributor Siron's Avatar
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    Re: Definite integral solution

    Correct!
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  3. #3
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    e^(i*pi)'s Avatar
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    Re: Definite integral solution

    Quote Originally Posted by celtic1234 View Post
    Hi all,
    Can you tell me if i am correct?

    Evaluate "integral sign"- [(2x^3)+(3x^2)-(4x)+5).dx between limits 5(b) and 0(a).
    Is this a minus sign or a hyphen?

    Quote Originally Posted by celtic1234 View Post
    Integrating each term individually gives:

    ((x^4)/2)+(x^3)-(2x^2)+(5x).

    and as b=x=5 and a=x=0

    {f(b)-f(a)}

    [((5^4)/2)+(5^3)-(2(5)^2)+(5(5))]-[((0^4)/2)+(0^3)-(2(0)^2)+(5(0))]

    [312.5+125-50+25]-[0]

    =412.5

    thanks
    John
    Your working is fine. If the thing in red above is a minus sign then your answer is -412.5 but if it is a hyphen you are correct
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  4. #4
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    Re: Definite integral solution

    Its a hyphen-Thanks so much for your help. I really need a book that goes from the beginning of calculus and has tons of problems from the very basic right through to the more complicated ones. The book i have gives an explanation and then gives extremely hard problems to solve-there is no solutions so it makes it difficult.
    Maybe books should be a separate thread.
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