# Total Differential

• Jan 19th 2013, 06:36 AM
jakeshinryu
Total Differential
* The volume V of a right circular cone of radius r and height h is given by V= 1/3 pi r2 h. Suppose the height increases from 10cm to 10.01cm, while the radius decreases from 12cm to 11.95cm. Use a total differential to approximate the change in (delta) V in volume.
• Jan 19th 2013, 06:44 AM
a tutor
Re: Total Differential
What

have

you

done?

Surely you know you can't just come on here, post a question without any comment and expect some help.

How are we supposed to know what you know, what you forgot, why you can't do this?
• Jan 19th 2013, 12:52 PM
hollywood
Re: Total Differential
The total differential is given by $dV = \frac{\partial{V}}{\partial{r}}dr + \frac{\partial{V}}{\partial{h}}dh$. The quantities dr and dh are given. I'm guessing partial derivatives are new for you - can you figure out what $\frac{\partial{V}}{\partial{r}}$ and $\frac{\partial{V}}{\partial{h}}$ are?

- Hollywood
• Jan 19th 2013, 02:11 PM
a tutor
Re: Total Differential
Was I a little mean?
• Jan 19th 2013, 03:42 PM
HallsofIvy
Re: Total Differential
No,

but

you

were

a

little

hard

to