Schulmathematik
F(5, 4) = 24·LN(5) + 84·LN(4) = 24·LN(640)
24·LN(x) + 84·LN(y) = 24·LN(640) --> y = 4·5^{2/7}/x^{2/7}
y' = - 8·5^{2/7}/(7·x^{9/7})
y'(5) = -8·5^{2/7}/(7·5^{9/7}) = -8/35 = -0.2286
Implizite Ableitung
F(x, y) = 24·LN(x) + 84·LN(y)
Fx = 24/x
Fy = 84/y
y'(x) = - Fx / Fy = - (24/x) / (84/y) = - 2·y/(7·x)
y'(5) = -2·4/(7·5) = -8/35 = -0.2286