Let's assume that $$ f:\mathbb{R}^{n} \rightarrow \mathbb{R}^{m} $$ is a linear mapping. What is its derivative?
I know what a linear mapping is. And I also know that the derivative $ Df(x_{0}) $ of $ f(x_{1},x_{2},...,x_{n}) = (f_{1},f_{2},...,f_{m}) $ at a point $x_{0}$ is a $m\times n$ matrix with values $t_{ij}=\frac{\partial f_{i}}{\partial x_{j}}$ at this point.
What should I WRITE to solve this problem? What is a right answer?