How to differentiate e^e^x?

Question

Ans at wolfram is e^(x+e^x). I need the calculation method.

Answer 1

You know that if y = e^u
y' = e^u u'

here, u=e^x, so
y' = (e^e^x) (e^x)
now just add exponents as usual when multiplying:

y' = e^(e^x+x)