It threw me a bit that I had to use the numpy norm function and for a while I was unsuccessfully trying to implement the function myself. So really this is a two part questions

Did I miss the fact in the course material

The norm function seems pretty straight forward, but I kept getting it wrong. Is there an example of the implementation somewhere?

Hi @lionbee ,
Are you using correct definition for norm ||x^{(i)} - \mu_j||^2?
As there are two columns per row for X[i] and mu_j, are you taking account both of columns when you are calculating norm for particular row?