Differentiable map
= Differentiable map
A map is differentiable at $x$ when it differs from an affine map with linear part $Df_x$ by $o(\lVert h\rVert)$ at $x+h$.
= Differentiable map
A map is differentiable at $x$ when it differs from an affine map with linear part $Df_x$ by $o(\lVert h\rVert)$ at $x+h$.