Prove or disprove the following: 5n^2 - 2n + 26 elementof O(n^2). forall a greaterthanorequalto 1: a^n element O(n!) forall a greaterthanorequalto 1: 2^n + a elementof O(2^n) forall a > 1: (f(n) elementof O(log_2 n)) doublerightarrow (f(n) elementof O(log_a n)) 2^n elementof O(n^log^2 n). 2^2^n + 1 elementof O(2^2^n)