# Math Help - ln[e^(x^3)]

1. ## ln[e^(x^3)]

my prof said
ln e^x = x
however, he wrote ln[e^(x^3)] = x^3 which i don't understand
because
if ln e^x = x, isn't ln[e^(x^3)] should be x^4 ?

can someone explain to me please?

2. The general formula is $ln \, e^{f(x)} = f(x)$ ..