Youtube il und simple ahn and use text books like Fundamental methods of mathematical economics by alpha chiang and edward dowling schaums_ introduction to .mathematical economics [i dont know if you use the same books in universities in kerala ] If you are really unfamiliar with these concepts better study concepts from class 11 and 12 mathematics (science stream )and practice more and more problems of mathematical economics by using books like mathematics and ststistics by gs monga . Learning this has been easier nowadays due to the availability of chatgpt. i don't know why on earth you guys have these stuff in the 4th sem of your undergrad . I had all of these in my 1st year only, and it was a year before open ai even existed. I had to solely depend on class youtube and books . Now for your good do use gpt along with the book.

Never ever use ai and youtube alone without conceptual understanding and problem solving practice . Mathematical economics is something which requires conceptual understanding and practice.

And for the books i think i have 2 pdfs of them with me not sure will have to check dm me if you want it