lec#2(A) types of perturbation theory #classification of perturbation theory

this is lec#2 part (A) , which contain
#types of perturbation theory
#classification of perturbation theory
#classification of perturbation theory
#time dependent perturbation theory
#time independent of perturbation theory
#Degenerate time independent perturbation theory.
#non degenerate time independent perturbation theory
also see