a)
f(x) = - x^2 + 6·x
f'(x) = 6 - 2·x = 0 --> x = 3 mit VZW von + nach -
f(3) = - 3^2 + 6·3 = 9 --> Hochpunkt (3|9)
b)
f(x) = 1/4·x^4 - 1/3·x^3 - x^2
f'(x) = x^3 - x^2 - 2·x
f''(x) = 3·x^2 - 2·x - 2
Hochpunkte f'(x) = 0
x^3 - x^2 - 2·x = 0 --> x = 2 ∨ x = -1 ∨ x = 0
f''(-1) = 3 ; f(-1) = -0.4167 --> TP(-1|-0.4167)
f''(0) = -2 ; f(0) = 0 --> HP(0|0)
f''(2) = 6 ; f(2) = -2.667 --> TP(2|-2.667)