f(x) = 3·x3·e- 3·x
f'(x) = 9·x2·e- 3·x + 3·x3·e- 3·x·(- 3)
f'(x) = 9·x2·e- 3·x - 9·x3·e- 3·x
Gemeinsame Faktoren ausklammern nach Distributivgesetz: ab ± ac = a(b ± c)
f'(x) = 9·[x2·e- 3·x - x3·e- 3·x]
f'(x) = 9·x2·[e- 3·x - x·e- 3·x]
f'(x) = 9·x2·e- 3·x·[1 - x]