f(x) = 20·√x / (10 - x)
Definitionsbereich x > 0 und x ≠ 10
f'(x) = 10·(x + 10) / (√x·(x - 10)^2)
f''(x) = 5·(3·x^2 + 60·x - 100)/(x^{3/2}·(10 - x)^3)
Wendetangente f''(x) = 0
3·x^2 + 60·x - 100 = 0 --> x = 20·√3/3 - 10 = 1.547
t(x) = f'(1.547) * (x - 1.547) + f(1.547) = 1.299·x + 0.9328