The function is f(x) = 1/2(x^T*A*x) = (b^T*x), where A is a matrix of nxn and b is a vector in R^n.

I'm just not sure what the function looks like. I can calculate the gradient and hessian matrix just fine--I just don't know how to write the function in a form that would allow me to do so.

I would greatly appreciate any guidance. Thanks.