I need to learn how to prove/disprove each of the following. Anyone able to do it in very simple way for a NON -mathematician to easily understand? ( NB -- NOT HOMEWORK)
a) $$n^2 + n + 1 = \Theta (n^2)$$ b) $$ n^2 = \omega(2^n)$$ c) $$n^2 = o (2^n)$$ d) $$\left|n \sin {\pi\cdot n\over 2}\right| = \Theta(n)$$