# Compute gradient of a matrix

I have this problem where I have to compute the gradient and justify all the steps. I'm not sure how to start this task of, when calculating for a matrix. Here is the problem: $$\nabla(\mathbf x^T\mathbf x)$$ where $$\mathbf x$$ is an $$n$$-vector.

Hint: $$x^Tx = x_1^2 + \ldots +x_n^2$$