# Matrix equations and derivatives

Hello!

I am completely new to Sage and Python. In order to get knowledge about Sage I'd like to find a way to express an equations like these

http://stats.stackexchange.com/questi...

User with nickname fabee had posted derivatives of contractive autoencoder regularizer, and I want to reproduce these results in Sage. It's a big challenge for Sage newbies like me. A few first attempts do not succeed so can you show me the way to do this task?