Note: I omitted two because they were images, too lazy to put them here properly.
36 Methods of Mathematical Proof
If the proof of a theorem is not immediately apparent, it may be because you are trying the wrong approach. Below are some effective methods of proof that might aim you in the right direction.
# Proof by obviousness: "The proof is so clear that it need not be mentioned."
# Proof by general agreement: "All in favor?..."
# Proof by imagination: "Well, we'll pretend it's true..."
# Proof by convenience: "It would be very nice if it were true, so..."
# Proof by necessity: "It had better be true, or the entire structure of mathematics would crumble to the ground."
# Proof by plausibility: "It sounds good, so it must be true."
# Proof by intimidation: "Don't be stupid; of course it's true!"
# Proof by lack of sufficient time: "Because of the time constraint, I'll leave the proof to you."
# Proof by postponement: "The proof for this is long and arduous, so it is given to you in the appendix."
# Proof by accident: "Hey, what have we here?!"
# Proof by insignificance: "Who really cares anyway?"
# Proof by profanity: (example omitted)
# Proof by definition: "We define it to be true."
# Proof by tautology: "It's true because it's true."
# Proof by plagiarism: "As we see on page 289,..."
# Proof by lost reference: "I know I saw it somewhere...."
# Proof by calculus: "This proof requires calculus, so we'll skip it."
# Proof by terror: When intimidation fails...
# Proof by lack of interest: "Does anyone really want to see this?"
# Proof by logic: "If it is on the problem sheet, it must be true!"
# Proof by majority rule: Only to be used if general agreement is impossible.
# Proof by clever variable choice: "Let A be the number such that this proof works..."
# Proof by tessellation: "This proof is the same as the last."
# Proof by divine word: "...And the Lord said, 'Let it be true,' and it was true."
# Proof by stubbornness: "I don't care what you say- it is true."
# Proof by simplification: "This proof reduced to the statement 1 + 1 = 2."
# Proof by hasty generalization: "Well, it works for 17, so it works for all reals."
# Proof by deception: "Now everyone turn their backs..."
# Proof by supplication: "Oh please, let it be true."
# Proof by poor analogy: "Well, it's just like..."
# Proof by avoidance: Limit of proof by postponement as it approaches infinity
# Proof by design: If it's not true in today's math, invent a new system in which it is.
# Proof by authority: "Well, Don Knuth says it's true, so it must be!"
# Proof by intuition: "I have this gut feeling."