Answer
$y' = -\dfrac{e^{1/x}}{x^2}$
Work Step by Step
In order to derivate this function you have to apply the chain rule
Let's make a «u» substitution to make it easier
$f(u) = e^u$
$u = \dfrac{1}{x}$
Derivate the function:
$f'(u) = u'e^u$
Now let's find u'
$u' =-\dfrac{1}{x^2} $
Then undo the substitution, simplify and get the answer:
$y' = -\dfrac{e^{1/x}}{x^2}$
