Past exam of the year 1 of the computer science course of the University of Oxford / 2019 / Discrete mathematics, continuous mathematics, and probability / 6 / c / i

Use a column gradient. By the multivariable chain rule,The scalar coefficients multiply the constant vectors ${\mathbf{a}}_i$. In particular $f^{\prime }(t)=-t{e}^{-t^2/2}$, although explicit differentiation of $f$ is not required.