Third and higher order Taylor expansions in several variables
In this post we show that it is possible to derive third and higer-order Taylor expansions for functions of several variables. Given that the gradient of a function is vector-valued and its Hessian is matrix-valued, it is natural to guess that its third-order gradient will be tensor-valued. However, not only is the use of tensors not very convenient, but in this context it is also unnecessary. Continue reading →