# How to use Lagrange multipliers?

I have the following optimal problem. Let $u_i \in \mathbb{C}$. Let $\lambda_i$ be unknowns and $\sum_{i=1}^n \lambda_i = F$ for some given $F \in \mathbb{C}$. Find $\lambda_1, \ldots, \lambda_n$ such that $\prod_{i=1}^{n} (u_i-\lambda_i)$ is maximal. I try to use Lagrange multiplier method. Let $G(\lambda_1, \ldots, \lambda_n, \lambda) = \prod_{i=1}^n (u_i-\lambda_i) - \lambda (\sum_{i=1}^n -F)$ and compute derivatives. But I cannot solve the equations. Do I need to use the function $\sum_{i=1}^{n} \log (u_i-\lambda_i)$ instead of $\prod_{i=1}^{n} (u_i-\lambda_i)$? Thank you very much.

Edit. $u_i, F \in \mathbb{R}$ are given.

The problem is solved.

2
2022-07-25 20:44:10
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