# Math Help - Total Differential

1. ## 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.

2. ## 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?

3. ## 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

4. ## Re: Total Differential

Was I a little mean?

No,

but

you

were

a

little

hard

to

6. ## Re: Total Differential

thanks for giving me the clue, i'm new to this. I can now solve the entire problem.

-Jakeshinryu

7. ## Re: Total Differential

I just need a hint to solve the problem, i admit that i am not an expert to this field so i need ideas that give me a clue to get a solution. Thanks for your criticsm.

-jakeshinryu