Question

Sendo f (x, y) = 3x³ + 4y², então o valor de
α2f / ax2 + a2f / ay2 é:

a) 9x ao quadrado +8y
b)18x + 8
c) 18
d) 0

Answer 1

$f(x, y) = 3x^{3} + 4 y^{2}$

αf/αx = 3 . 3 . x^2 = 9x²
α²f/αx² = 9 . 2 . x = 18x

αf/αy = 4 . 2 . y = 8y
α²f/αy² = 8 . 1 = 8

Logo

α²f/αx² + α²f/αy² = 18x - 8

Alternativa b