Need some help in understanding how the double summation got converted into single summation while doing partial derivative, the exact screenshot can be accessed at https://ibb.co/PWzR66w . It would be nice if some references are also provided, to understand this concept.
Partial Derivative
Hey @tisandas2011, i would strongly recommend watching the video again, if still unable to understand, than plz ask again, i will ensure that you get it.
Thanks for the help. Got the derivation from other sources.
