You should follow NPTEL Channels and streams of Top IIT Professors on Youtube. As far as I remember from my first Year, for Engineering Mathematics, you should follow Videos ans Slides of Prof Jitendra Kumar, IIT Kharagpur and Engineering Physics from Prof Somenath Ghosh, IIT Kharagpur.

There are many good channels for C/C++ Programming and you can also take help from Geeks4Geeks and HackerRank.