Question

como calcular a derivada de y = 3x3.(x2 + 8x)

Answer 1

$y=3x^3\cdot (x^2+8x)$

Derivando usando a Regra do Produto:

$\dfrac{dy}{dx}=\dfrac{d}{dx}(3x^3)\cdot (x^2+8x)+3x^3\cdot \dfrac{d}{dx}(x^2+8x)\\\\\\ \dfrac{dy}{dx}=(3\cdot 3x^{3-1})\cdot (x^2+8x)+3x^3\cdot (2x+8)\\\\\\ \boxed{\begin{array}{c}\dfrac{dy}{dx}=9x^2\cdot (x^2+8x)+3x^3\cdot (2x+8) \end{array}}$