Sean
f(u,v) = (tg(u-1) - e^v, u^2 - v^2)
g(x,y) = (e^(x-y), x-y)
Calcular f o g y D(f o g)(1,1)
Ambas funciones son de R2 en R2, la composición también sera de R2 en R2
$$fog(x,y)=(tg(e^{x-y}-1)-e^{(x-y)},\;e^{(2x-2y)}-(x-y)^2)
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D(fog)(x,y)=
\begin{pmatrix}
\frac{\partial (fog)_1}{\partial x}&\frac{\partial (fog)_1}{\partial y}\\
\frac{\partial (fog)_2}{\partial x}&\frac{\partial (fog)_2}{\partial y}
\end{pmatrix}=
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\begin{pmatrix}
(1+tg^2(e^{(x-y)}-1))e^{x-y}-e^{x-y}&-(1+tg^2(e^{(x-y)}-1))e^{x-y}+e^{x-y}\\
2e^{(2x-2y)}-2(x-y)&-2e^{2x-2y}+2(x-y)
\end{pmatrix}
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·
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D(fog)(1,1)=
\begin{pmatrix}
[1+tg^2(e^0-1)]e^0-e^0&-[1+tg^2(e^0-1)]e^0+e^0\\
2e^0-2·0&-2e^0+2·0
\end{pmatrix}=
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.
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\begin{pmatrix}
0&0\\
2&2
\end{pmatrix}$$
Y eso es todo.