WebProof by Cases. Proving a claim "by cases" is a technique reminiscent of the old adage "Divide and Conquer!". Suppose one is trying to prove some statement S. If one knows that one of two or more cases must occur, then one can prove S is true by showing it must be true in each such case. With any luck, each individual case will be more simply ... WebHere are some examples of how you might split up a proof into cases (Step 1), depending on what type of number the conjecture concerns: Family. Possible cases. a ∈Z a ∈ Z. Case 1: a a is even. Case 2: a a is odd. Case 1: a =3k a = 3 k. Case 2: a =3k+1 a = 3 k + 1. Case 3: a =3k+2 a = 3 k + 2.
General Comments Proofs by Mathematical Induction - UMD
WebThe proof by example fallacy involves attempting to derive general conclusions from one or a few examples. In its simplest form, proof by example works like this: X, which is in the … WebThe following is an example of a direct proof using cases. Theorem 1.2. If q is not divisible by 3, then q2 1 (mod 3). Proof. If 3 - q, we know q 1 (mod 3) or q 2 (mod 3). ... A proof … download file smart hafiz
1.5 METHODS OF PROOF - JMU
WebJul 7, 2024 · Solution. hands-on exercise 3.2. 2. Show that if x 3 + 6 x 2 + 12 x + 8 = 0, then x = − 2. The last example demonstrates a technique called proof by cases. There are two possibilities, namely, either (i) x 2 + 1 = 0, or (ii) x − 7 = 0. The final conclusion is drawn after we study these two cases separately. WebMay 12, 2024 · 4. A classical example of proof by exhaustion is to establish an integer N is prime by trial divisions. One uses trial division by candidates for divisors up to N. This can be made slightly less exhausting by using the method of the Sieve of Eratosthenes. WebProof by Cases: A proof by cases is one in which you prove \(\forall x\in D, P(x)\) by breaking \(D\) into smaller subsets. We saw an example in Theorem 4.3.5, where we broke \(D\) into the set of primes and the set of composites. Then each case is proven separately. Make sure you state each case clearly. download file smbclient