E(x) = - 1800/30^2·(x - 30)^2 + 1800 = 120·x - 2·x^2
p(x) = 120 - 2·x
K(x) = a·x + b
G(x) = 120·x - 2·x^2 - (a·x + b) = - 2·x^2 - a·x + 120·x - b
G'(x) = - 4·x - a + 120
Gewinnmaxumum
G'(26) = 0
- 4·26 - a + 120 = 0 --> a = 16
G(26) = 552
- 2·26^2 - 16·26 + 120·26 - b = 552 --> b = 800
K(x) = 16·x + 800