In Exercises $1-6,($ a express $d w / d t$ as a function of $t,$ both by using the Chain Rule and by expressing $w$ in terms of $t$ and differentiating directly with respect to $t .$ Then (b) evaluate $d w / d t$ at the given value of $t$.
$$w=2 y e^{x}-\ln z, \quad x=\ln \left(t^{2}+1\right), \quad y=\tan ^{-1} t, \quad z=e^{t};$ $t=1$$