multi-variable

[Math] Differentiability of MultivariableFunctions

Differentiability $\textbf{f}:\mathbb{R}^n \to \mathbb{R}^m$ 이고, $\textbf{a} \in \mathbb{R}^n$이면서 $\textbf{f}$의 domain에 속한다고 하자. 이 때 $$ \underset{\textbf{x}\to\textbf{a}}{\lim} \frac{\textbf{f}(\textbf{x})-\textbf{f}(\textbf{a})-\textbf{L}\langle \textbf{x}-\textbf{a}\rangle}{||\textbf{x}-\textbf{a}||_2}=\textbf{0} $$ $||\textbf{x}-\textbf{a}||_2$ : $\textbf{x}$와 $\textbf{a}$의 difference vector의..