Exercise 7.8

The weight matrices are the same as in example 7.1. For the data point $x=2$, $y=1$, we have

, $s^{(1)}$ is the same as before,

So $x^{(1)}=\left[\begin{array}{c}\hfill 1\hfill \\ \hfill 0.7\hfill \\ \hfill 2\hfill \end{array}\right]$, and $s^{(2)}=\left[\begin{array}{c}\hfill -2.1\hfill \end{array}\right]$,

Apply backpropagation and note that ${𝜃}^{\prime }(s^{(l)})=1$ to compute