f(x) = - 5·x^2·e^{3 - 3.5·x}
f'(x) = e^{3 - 3.5·x}·(17.5·x^2 - 10·x)
f''(x) = e^{3 - 7·x/2}·(- 61.25·x^2 + 70·x - 10)
f''(0.88) = 3.848 > 0 --> wahr
f'(0.89) = 4.4227 > 4.42 --> falsch
f'(1) = 4.549 <> 0 --> falsch
f'(0.34) = -8.414 --> falsch
f''(0.22) = 22.65 --> falsch
