f(x) = x^4 - 3x^2 - 4x + 3
f '(x) = 4x^3 - 6x - 4
f ''(x) = 12x^2 - 6
Tangente an der Stelle -1
f(-1) = 5
f '(-1) = -2
t(x) = -2 * (x + 1) + 5 = -2x + 3
Wendetangenten
f ''(x) = 0
12x^2 - 6 = 0
x = +- √0.5
f(√0.5) = 7/4 - 2√2
f '(√0.5) = - 2√2 - 4
f(-√0.5) = 2√2 + 7/4
f '(-√0.5) = 2√2 - 4
tw1(x) = (-2√2 - 4) * (x - √0.5) + 7/4 - 2√2 = 15/4 - x·(2√2 + 4)
tw2(x) = (2√2 - 4) * (x + √0.5) + 2√2 + 7/4 = x·(2√2 - 4) + 15/4
Skizze: