Hello all, I am taking a course on time series. Despite just starting class, I was already given a problem to solve, and am stuck on this one. (taken from Introduction to Time Series and Forecasting by Brockwell, problem A.8)

Suppose that $\displaystyle X = (X_{1}, X_{2}, ... ,X_{n})' \sim N(\mu,\Sigma)$ with $\displaystyle \Sigma$ nonsingular.

If A is a symmetric n x n matrix, show that $\displaystyle E(X'AX) = $trace$\displaystyle (A\Sigma) + \mu'\Sigma\mu $

Any help would be much, much appreciated. Thank you!