This is a nice intro to linear algebra but doesn't really get into how it's related to deep learning. A good read is Vector, Matrix, and Tensor Derivatives[0], which goes into the linear algebra needed in multi-layer neural networks, specifically during the backpropogation phase.<p>[0] <a href="http://cs231n.stanford.edu/vecDerivs.pdf" rel="nofollow">http://cs231n.stanford.edu/vecDerivs.pdf</a>