Author Topic: maxima.......question...very tough  (Read 2149 times)

Offline cashem'up

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maxima.......question...very tough
« on: September 09, 2009, 04:59:51 pm »
hey guys very long question...neone has P1 pg110 q16....very hard...just see if u can answer Thanks

Offline Ghost Of Highbury

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Re: maxima.......question...very tough
« Reply #1 on: September 09, 2009, 05:01:16 pm »
hey guys very long question...neone has P1 pg110 q16....very hard...just see if u can answer Thanks
which book??

which subject?/

plzz post ur question so that some1 can help u out
 :)
divine intervention!

nid404

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Re: maxima.......question...very tough
« Reply #2 on: September 09, 2009, 05:03:48 pm »
Is it the cylinder ans sphere question...i'll answer it after im back from dinner
or post the question..not too big..som1 else can answer it in the meantime

Offline cashem'up

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Re: maxima.......question...very tough
« Reply #3 on: September 09, 2009, 05:47:44 pm »
yep that question....its

1. a circular cylinder is to fit inside a sphere of radiius 10cm. Calculate the maximum possible volume of the cylinder(probably best to take height of cylinder as your independent variable).

nid404

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Re: maxima.......question...very tough
« Reply #4 on: September 09, 2009, 06:23:33 pm »
I'm not getting it right unfortunately but I'll keep trying...I've gone wrong somewhere but can't figure out

Offline cashem'up

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Re: maxima.......question...very tough
« Reply #5 on: September 09, 2009, 06:42:13 pm »
yeah it seems to be a tricky question......letz wait for astar........

nid404

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Re: maxima.......question...very tough
« Reply #6 on: September 09, 2009, 06:50:43 pm »
I guess that's what we should do...I managed to find the radius of the cylicnder as 6.67cm...but my finally answer is wrong

Offline astarmathsandphysics

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Re: maxima.......question...very tough
« Reply #7 on: September 09, 2009, 06:56:48 pm »
The answer is in the attached doc. I am messing about with openoffice trying to create webpages now.
« Last Edit: September 09, 2009, 07:03:26 pm by astarmathsandphysics »

nid404

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Re: maxima.......question...very tough
« Reply #8 on: September 09, 2009, 07:12:29 pm »
oh that was that....i simply went into crap..
Thanks sir :)

Offline cashem'up

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Re: maxima.......question...very tough
« Reply #9 on: September 10, 2009, 05:53:21 pm »
hey astar.....the answer is not comin rite m gettin 855cm3 but the actual answer is 2420cm3


Offline astarmathsandphysics

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Re: maxima.......question...very tough
« Reply #10 on: September 10, 2009, 06:47:17 pm »
Did you download the pdf I posted earlier in this thread? What did you get for tanx?

Offline cashem'up

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Re: maxima.......question...very tough
« Reply #11 on: September 10, 2009, 07:00:48 pm »
tanx= 0.707
and  x=35.26
then i substituted in orig.. eqn for VOl

Offline astarmathsandphysics

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Re: maxima.......question...very tough
« Reply #12 on: September 10, 2009, 07:01:58 pm »
r=10 for the sphere butthe radius of the cynder is 2rsinx =2*10*1/sqrt5=8.94 and height is 2rcosx=20*2/sqrt5=17.9 so volume=3.14*8.95^2*17.9=4489

Offline astarmathsandphysics

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Re: maxima.......question...very tough
« Reply #13 on: September 10, 2009, 07:03:56 pm »
The formula for the volume is wrong. I should have included a factor 8 cos I only had half the height and half the volume. Also there are 2 x's in the diagram but there should only be one, at the edge of the circle.

Offline cashem'up

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Re: maxima.......question...very tough
« Reply #14 on: September 12, 2009, 05:19:15 am »
yes i can understand but the actual given answer is 2420.....