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| 20 May 2015 12:17 AM |
Ugh, end-of-the-year struggles are real:
The formula for the volume of a cone is V=(1/3)(pi)r^2(h). Find the rate of change of the volume if dr/dt is 2 inches per minute and h = 3r when (a) r = 6 inches and (b) r = 24 inches.
I'm assuming I take the derivative of the volume equation, and since it's directly proportional to time, it's dV/dt = (1/3)...
After the (1/3), I don't know what to do. Do I place h with 3r and then differentiate using the chain rule, or do I use the product rule? |
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Lomhk
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| Joined: 08 Feb 2014 |
| Total Posts: 2083 |
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| 20 May 2015 12:20 AM |
Would help but english isn't my native language |
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Gradiance
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9draco
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| Joined: 13 Nov 2010 |
| Total Posts: 5841 |
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| 20 May 2015 12:23 AM |
| If youre done making yourself look "smart" In a kids game, go check youtube tutorials or google it. |
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| 20 May 2015 12:26 AM |
What about this one, it's a little easier but I'm still kinda clueless. It's my last lesson for the year, it's a hard one:
All edges of a cube are expanding at a rate of 3 centimeters per second. How fast is the volume changing when each edge is (a) 1 centimeter and (b) 10 centimeters?
I'm assuming I use the equation for the volume of a cube: V = b*w*h however since it's a cube, the base and width are constant, so it's b^2 or w^2. Then I differentiate the sides?
HELP |
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| 20 May 2015 12:26 AM |
my god, my final is on tuesday and I don't have this all down I'm screwed
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| 20 May 2015 12:28 AM |
I like to lower my expectations
Makes everything easier |
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wuh
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| Joined: 21 Mar 2010 |
| Total Posts: 1072 |
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| 20 May 2015 12:28 AM |
| why are you asking a bunch of 7th graders for calculus help? |
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| 20 May 2015 12:29 AM |
I want to go into engineering but the field I want to go into won't ever use this level of calculus Aghhhh I'm so close to the summer Just got to finish this last hw assignment, and do my final. C.C |
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9draco
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| Joined: 13 Nov 2010 |
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| 20 May 2015 12:29 AM |
If youre done making yourself look "smart" In a kids game, go check youtube tutorials or google it. [2]
By the way edge (a) stays at 3CM/Sec since its only 1 CM. |
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| 20 May 2015 12:30 AM |
@sitar mixer/european and a couple other's know this stuff + FB is dead and this is due tomorrow, and I don't know where else to get help Google is giving me like, college level stuff which I don't understand
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| 20 May 2015 12:30 AM |
youtube im only in advanced algebra :p
"You've got enemies? Good. That means you actually stood up for something." -Eminem |
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Mixernxer
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| Joined: 06 Sep 2008 |
| Total Posts: 14112 |
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| 20 May 2015 12:30 AM |
| @9 dont confuse asking for help with bragging |
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| 20 May 2015 12:31 AM |
| Impossible 9draco, you can't substitute before differentiation. |
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Mixernxer
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| Joined: 06 Sep 2008 |
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| 20 May 2015 12:32 AM |
although I can't help you, heres a link
http://math.stackexchange.com/questions/234604/how-do-you-calculate-the-rate-of-change-of-the-volume-of-a-cone-at-a-given-heigh |
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9draco
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| Joined: 13 Nov 2010 |
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| 20 May 2015 12:32 AM |
| @Mixer, Yeah go to a kids game and ask a calculus question and expect some kids to answer him. -_- |
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| 20 May 2015 12:32 AM |
| I like no nothing about math, I'm excellent at history doe. |
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Mixernxer
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| Joined: 06 Sep 2008 |
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| 20 May 2015 12:33 AM |
| @9 he seeks advice from people who know math, once you understand formulas are logic generalizations math becomes easier |
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9draco
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| Joined: 13 Nov 2010 |
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| 20 May 2015 12:33 AM |
| Oh I didnt notice that you asked for this, "volume changing" I thought you simply have to divide the edge's length with the speed its expanding. |
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9draco
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| Joined: 13 Nov 2010 |
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| 20 May 2015 12:34 AM |
| @Mixer, if so, he could ask in the "scripters" sub-forum, there are many geniuses in math over there. |
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| 20 May 2015 12:34 AM |
@mix ty I just needed to see what the derivative of the cone's volume formula was
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