Write out the equations for a deep neural network that takes Di $=5$ inputs, Do $=4$

outputs and has three hidden layers of sizes D$1=20,$ D$2=10,$ and D$3=7,$ respectively, in

both the forms of equations $4\mathrm{.}15$ and $4\mathrm{.}16.$ What are the sizes of each weight matrix $$ and

bias vector $\backslash$beta $$

$?$