Direct Proofs - Stanford University

Direct Proofs A direct proof is the simplest type of proof. Starting with an initial set of assumptions, apply simple logical steps to derive the result. Directly prove that the result is true. Contrasts with indirect proofs, which we'll see on Friday.

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Introduction to mathematical arguments

prove any type of statement. This chart does not include uniqueness proofs and proof by induction, which are explained in §3.3 and §4. Apendix A reviews some terminology from set theory which we will use and gives some more (not terribly interesting) examples of proofs. 1

  Proof

Logic, Sets, and Proofs - Amherst College

A set is a collection of objects, which are called elements or members of the set. Two sets are equal when they have the same elements. ... strategies for di erent types of proofs. Direct Proof. The simplest way to prove A )B is to assume A (the \hypothe-sis") and prove B (the \conclusion"). See Proof 2 in Section 5 for a direct proof of

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A GUIDE TO PROOFS IN LINEAR ALGEBRA

Logical deduction was the fourth element in our list of ingredients for writing proofs. Much of our logical structure is buried in the development of axiomatic structure and set theory. From this we get the theorems we’ve previously developed in mathematics such as Euclidean geometry, algebra, trigonometry, and calculus.

  Linear, Proof, Algebra, Linear algebra

THE GAUSSIAN INTEGRAL - University of Connecticut

We will give multiple proofs of this result. (Other lists of proofs are in [4] and [9].) The theorem is subtle because there is no simple antiderivative for e 21 2 x (or e 2x2 or e ˇx). For comparison, Z 1 0 xe 1 2 x2 dxcan be computed using the antiderivative e 1 2 x2: this integral is 1. 1. First Proof: Polar coordinates

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Logic, Sets, and Proofs - Amherst

Logic, Sets, and Proofs David A. Cox and Catherine C. McGeoch Amherst College 1 Logic Logical Operators. A logical statement is a mathematical statement that can be ... A set is a collection of objects, which are called elements or members of the set. Two sets are equal when they have the same elements.

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Basic Proofs - Loyola University Maryland

There are four basic proof techniques to prove p =)q, where p is the hypothesis (or set of hypotheses) and q is the result. 1.Direct proof 2.Contrapositive 3.Contradiction 4.Mathematical Induction What follows are some simple examples of proofs. You very likely saw these in MA395: Discrete Methods. 1 Direct Proof

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Proof Techniques - Stanford University Computer Science

monly seen in proofs. 1.1.1 Proof by contrapositive Consider the statement \If it is raining today, then I do not go to class." This is logically equivalent to the statement \If I go to class, then it is not raining today." So if we want to prove the rst statement, it su ces to prove the second statement (which is called the contrapositive).

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Chapter 1. Metric spaces - Proofs covered in class

5 A set is open if and only if it is a union of open balls. Proof. Suppose first that U is a union of open balls. Then U is a union of open sets by part 4, so it is open itself by part 2. Conversely, suppose that U is an open set. Given any x ∈ U, we can then find some ε x > 0such that B(x,ε x)⊂ U. This gives {x} ⊂ B(x,ε x)⊂ U

  Proof

Identity 2. - gatech.edu

Further, x ∈ A and x 6∈B also by definition of set difference. Thus x ∈ A and x 6∈B and x 6∈C, which implies x 6∈(BorC). Hence, x 6∈(B∪C) by definition of union. Thus, given x ∈ A we have x ∈ A−(B∪C) by definition of set difference. 1. Identity 4. Let A, B and C be sets. Show that