Hi!
Für die Normalensteigung gilt ja:
m= -1/f '(x) = -1/2
f '(x)=3/32*x2
Einsetzen:
-1/(3/32*x2)= -1/2 | *3/32*x2
-1= -1/2*(3/32*x2 )
-1= -3/64*x2 |: -3/64
64/3=x2 |√
x= ±√(64/3)
~plot~ 1/32 x^3 - 11/4;x=sqrt(64/3);x=-sqrt(64/3); [[ -8| 8 | -8 | 8 ]] ~plot~