Search results
Results from the WOW.Com Content Network
All integers are rational, but there are rational numbers that are not integers, such as −2/9. Real numbers (): Numbers that correspond to points along a line. They can be positive, negative, or zero. All rational numbers are real, but the converse is not true. Irrational numbers (): Real numbers that are not rational.
Dov Jarden gave a simple non-constructive proof that there exist two irrational numbers a and b, such that a b is rational: [28] [29] Consider √ 2 √ 2; if this is rational, then take a = b = √ 2. Otherwise, take a to be the irrational number √ 2 √ 2 and b = √ 2. Then a b = (√ 2 √ 2) √ 2 = √ 2 √ 2 · √ 2 = √ 2 2 = 2 ...
Rational numbers have irrationality exponent 1, while (as a consequence of Dirichlet's approximation theorem) every irrational number has irrationality exponent at least 2. On the other hand, an application of Borel-Cantelli lemma shows that almost all numbers, including all algebraic irrational numbers , have an irrationality exponent exactly ...
The sum, difference, product, and quotient (if the denominator is nonzero) of two algebraic numbers is again algebraic: For any two algebraic numbers α, β, this follows directly from the fact that the simple extension (), for being either +, , or (for ) /, is a linear subspace of the finite-degree field extension (,), and therefore has a ...
The sum of the reciprocals of all the Fermat numbers (numbers of the form + ) (sequence A051158 in the OEIS) is irrational. The sum of the reciprocals of the pronic numbers (products of two consecutive integers) (excluding 0) is 1 (see Telescoping series).
[2] [3] The adjective real, used in the 17th century by René Descartes, distinguishes real numbers from imaginary numbers such as the square roots of −1. [4] The real numbers include the rational numbers, such as the integer −5 and the fraction 4 / 3. The rest of the real numbers are called irrational numbers.
The number x is called a normal number (or sometimes an absolutely normal number) if it is normal in base b for every integer b greater than 1. [ 7 ] [ 8 ] A given infinite sequence is either normal or not normal, whereas a real number, having a different base- b expansion for each integer b ≥ 2 , may be normal in one base but not in another ...
Originally, a product was and is still the result of the multiplication of two or more numbers.For example, 15 is the product of 3 and 5.The fundamental theorem of arithmetic states that every composite number is a product of prime numbers, that is unique up to the order of the factors.