#### Answer

$y' = e^{tan (t)} \times sec^2(t)$

#### Work Step by Step

$y = e^{tan (t)}$
$y' = (e^{tan (t)})'$
The inner function is $g(t) = tan(t)$
and the outer function is $f(u) = e^u$
$f'(u) = e^u$
$y' = (e^{tan (t)})' = e^{g(t)}\times g'(t) = e^{tan (t)} \times sec^2(t)$