This question looks pretty easy and hard at the same time. Here's how it goes:
Let A and B be symmmetric nxn matrices. Show that A + B is also symmetric.
To me this sounds like a pretty obvious fact, well, if its not obvious I still have a good idea of why this is true, but I'm new to university level maths and I don't really know how I would go about writing a formal proof for this. Any help would be much appreciated. =D