Algorithms Big-O notation

[ambert123]

2^(2^n)=O(2^n). Is it true or false?

Thanks in advance

[sepp2k]

Do you think it's true or false? What have you trieed to prove or disprove it? What's the definition of big-Oh - how would 2^(2^n) need to relate to 2^n for 2^(2^n) to be in O(2^n)?

[amina.bm]

Greetings,

First of all, let g and f be two given functions :

f(x)belongs to O(g(x)) iff: there is some c of R+ such that:

                               f(x)<= c*(g(x)) . . .(1)

Thus, from (1) we can conclude that 2^(n)<= 2^(2^n) where c=1,

Then, 2^(n) belongs to O(2^(2^n)).

[alexstone]

Interesting how can this algoritm being used in computer science