I really do not get proofs AT ALL. Stuff like this.... "Prove that (n+1)2 [tex]\geq[/tex]3n if n is a positive integer with n[tex]\leq[/tex]4." Proof by exhaustion would be applied here.. what the book tells me. "Show that there are no solutions in integers x and y of x2+3y2=8." Then there's also "Constructive Existence Proof" and "Nonconstructive proof". No idea how to do any one of them. How do I approach those equations, and how do I know which proof I need to use??