Say $A$ and $B$ are symmetric, positive definite matrices.
I've proved that $\det(A+B) \ge \det(A) + \det(B)$
$$\det(A+B) \ge \det(A) + \det(B)$$
in the case that $A$ and $B$ are two dimensional.
Is this true in general for $n$-dimensional matrices?
Is itthe following even true that $\det(A+B) \ge \det(A)$ [as this?
$$\det(A+B) \ge \det(A)$$
This would also be enough..]
Thanks.