Year 12s: what will be the first way you research your future options? >>

Further Maths rates of change and second differentiation

forxer

No sure how about to start this. Help!
Screen Shot 2016-09-19 at 14.11.46.png

Reply 1

RDKGames

Study Forum Helper

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.

Reply 2

Zacken

Duplicate http://www.thestudentroom.co.uk/showthread.php?t=4325948

Reply 3

forxer

Original post by Zacken

Duplicate http://www.thestudentroom.co.uk/showthread.php?t=4325948

if your not going to be helpful jog on or do you not have a life

Reply 4

RDKGames

Study Forum Helper

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.

Reply 5

forxer

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.