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    Ok I know theres probably a really simple answer to this, but I'm so stressed at the minute I can barely think lol. How do you find the integral between 1 and 4 of |(4u squared + 8u + 4) all divided by u squared? By the way the answer should be 15 + 16ln2
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    (Original post by seans443)
    Ok I know theres probably a really simple answer to this, but I'm so stressed at the minute I can barely think lol. How do you find the integral between 1 and 4 of |(4u squared + 8u + 4) all divided by u squared? By the way the answer should be 15 + 16ln2
    Is that a modulus sign I see?

    Is your integral:
    \displaystyle\int^4_1 \dfrac{|4u^2+8u+4|}{u^2} du

    Or the same as above without the mod signs? If it's the latter then use the fact that \dfrac{a+b+c}{d} \equiv \dfrac{a}{d} + \dfrac{b}{d} + \dfrac{c}{d} to break down the integrand to something you can integrate easily.
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    Take out a factor of 4 from the top line and you should note that it's a perfect square. Now simplify the integrand and then integrate.
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    (Original post by Farhan.Hanif93)
    Is that a modulus sign I see?

    Is your integral:
    \displaystyle\int^4_1 \dfrac{|4u^2+8u+4|}{u^2} du

    Or the same as above without the mod signs? If it's the latter then use the fact that \dfrac{a+b+c}{d} \equiv \dfrac{a}{d} + \dfrac{b}{d} + \dfrac{c}{d} to break down the integrand to something you can integrate easily.
    Oops that was a typo, there shouldnt have been a modulus sign in there. Thanks for your help, still didnt work out for me properly though lol
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    (Original post by seans443)
    Oops that was a typo, there shouldnt have been a modulus sign in there. Thanks for your help, still didnt work out for me properly though lol
    Show your working and I'll try to tell you what part you did wrong.
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    (Original post by Farhan.Hanif93)
    Show your working and I'll try to tell you what part you did wrong.
    I've got it now, just made a stupid mistake at the end. Thanks very much for the help
 
 
 
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