Question

Qual é a derivada total dz/dt, sendo z = 2x2 -4xy + 2y2 , onde x(t) = t e y (t) = t ?

Answer 1

$z=2x^2-4xy+2y^2\\\\x=t\\\\y=t\\\\\\z=2(t)^2-4(t)(t)+2(t)^2\\\\z=2t^2-4t^2+2t^2\\\\z=0\\\\\dfrac{\delta z}{\delta t}=0$