Quantifying efficiency: O( ), Omega( ), Theta( ) 

did you find any better videos?

it can be O(n^2) and after that he also clarifies that it could be O(n) also.It was just an example.

@@raghav.73 ​why cant for c = 101 n0 = 2 itself?? it stays true all the constraints. So why not ? and that's best na - as what I say is LEAST UPPER BOUND.

It has been mentioned in the first lecture that the course takers should know basics of programming and data structures. And usually a first course on ds and progg. talks about basic ideas of algorithms and its analysis

​@@shashanks8453 why cant for c = 101 n0 = 2 itself?? it stays true all the constraints. So why not ? and that's best na - as what I say is LEAST UPPER BOUND.

for n^3 Ω n^2, n0 =1, and not n0=1 This is because, for n=0.9, (.9)^3 < (.9)^2 this is true for any n

This is especially when n is non-integer. But when n is integer, above is true.