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Further Maths rates of change and second differentiation Watch

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    No sure how about to start this. Help!
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    Lay out the information.

    S=\pi r^2 + 2\pi r h

    300=\pi r ^2 h \Rightarrow h=\frac{300}{\pi r^2}

    Sub h into S and differentiate it with respect to r. Make it equal 0 and solve for r. Check this gives the minimum and plugging it through the second differential.
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    Duplicate http://www.thestudentroom.co.uk/show....php?t=4325948
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    if your not going to be helpful jog on or do you not have a life
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    (Original post by forxer)
    if your not going to be helpful jog on or do you not have a life
    But you literally posted the same thing on the other thread, no need for a duplicate.
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    (Original post by RDKGames)
    Lay out the information.

    S=\pi r^2 + 2\pi r h

    300=\pi r ^2 h \Rightarrow h=\frac{300}{\pi r^2}

    Sub h into S and differentiate it with respect to r. Make it equal 0 and solve for r. Check this gives the minimum and plugging it through the second differential.
    so i got r as 1/300pi for the first differentiate
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    (Original post by forxer)
    if your not going to be helpful jog on or do you not have a life
    That is very helpful for everyone else, it avoids duplication of efforts
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    (Original post by SeanFM)
    That is very helpful for everyone else, it avoids duplication of efforts
    true my bad
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    (Original post by forxer)
    so i got r as 1/300pi for the first differentiate
    Show your working if you get stuck.
 
 
 
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