# Optimisation Problem

Could you please explain what the person means by "vanishing determinant condition," and how he derives that $h=2\sqrt{(2r+R)(r+2R)} $

and also please explain the second case because I don't understand why he says "return to the cartesian system" and how he gets those equations.

Here's the website again: https://math.stackexchange.com/questions/4024363/optimizing-a-conical-frustum-using-partial-differentiation/4024472#4024472

/>

Thanks a lot!

## Answer

**Answers can be viewed only if**

- The questioner was satisfied and accepted the answer, or
- The answer was disputed, but the judge evaluated it as 100% correct.

The answer is accepted.

- answered
- 136 views
- $14.76

### Related Questions

- Mean value formula for the laplace equation on a disk
- True-False real analysis questions
- Is $\sum_{n=1}^{\infty}\frac{\arctan (n!)}{n^2}$ convergent or divergent?
- Calculus - Derivatives (help with finding a geocache)
- Method of cylindrical shells
- Let $f:U\subset\mathbb{R} ^3\rightarrow \mathbb{R} ^2$ given by $f(x,y,z)=(sin(x+z)+log(yz^2) ; e^{x+z} +yz)$ where $U = { (x, y, z) ∈ R^3| y, z > 0 }.$ Questions Inside.
- Integral of trig functions
- Riemann Sums for computing $\int_0^3 x^3 dx$