exp(-0.08x+0.0024x^2-0.00002x^3)
let u = -0.08x+0.0024x^2-0.00002x^3
Then f = exp(u)
and, by the chain ruike, df/dx = (df/du)*(du/dx)
we now have, df/du = exp(u) and du/dx = -0.08 + 0.0048x - 0.00006x^2
Therefore, df/dx = (exp(u))*(-0.08 + 0.0048x - 0.00006x^2)
df/dx = (-0.08 + 0.0048x - 0.00006x^2)*exp(-0.08x+0.0024x^2-0.00002x^3)