Limit Comparison Test

	Limit Comparison Test In mathematics, the limit comparison test (LCT) (in contrast with the related direct comparison test) is a method of testing for the convergence of an infinite series. Statement Suppose that we have two series \Sigma_n a_n and \Sigma_n b_n with a_n\geq 0, b_n > 0 for all n. Then if \lim_ \frac = c with 0 < c < \infty , then either both series converge or both series diverge. Proof Because $\lim_ \frac = c$ we know that for every $\varepsilon > 0$ there is a positive integer $n_0$ such that for all $n \geq n_0$ we have that $\left, \frac - c \ < \varepsilon$ , or equivalently : $- \varepsilon < \frac - c < \varepsilon$ : $c - \varepsilon < \frac < c + \varepsilon$ : $(c - \varepsilon)b_n < a_n < (c + \varepsilon)b_n$ As $c > 0$ we can choose $\varepsilon$ to be sufficiently small such that $c-\vare ...$ [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Mathematics Mathematics is a field of study that discovers and organizes methods, Mathematical theory, theories and theorems that are developed and Mathematical proof, proved for the needs of empirical sciences and mathematics itself. There are many areas of mathematics, which include number theory (the study of numbers), algebra (the study of formulas and related structures), geometry (the study of shapes and spaces that contain them), Mathematical analysis, analysis (the study of continuous changes), and set theory (presently used as a foundation for all mathematics). Mathematics involves the description and manipulation of mathematical object, abstract objects that consist of either abstraction (mathematics), abstractions from nature orin modern mathematicspurely abstract entities that are stipulated to have certain properties, called axioms. Mathematics uses pure reason to proof (mathematics), prove properties of objects, a ''proof'' consisting of a succession of applications of in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Direct Comparison Test In mathematics, the comparison test, sometimes called the direct comparison test to distinguish it from similar related tests (especially the limit comparison test), provides a way of deducing whether an infinite series or an improper integral converges or diverges by comparing the series or integral to one whose convergence properties are known. For series In calculus, the comparison test for series typically consists of a pair of statements about infinite series with non-negative ( real-valued) terms: * If the infinite series \sum b_n converges and 0 \le a_n \le b_n for all sufficiently large ''n'' (that is, for all n>N for some fixed value ''N''), then the infinite series \sum a_n also converges. * If the infinite series \sum b_n diverges and 0 \le b_n \le a_n for all sufficiently large ''n'', then the infinite series \sum a_n also diverges. Note that the series having larger terms is sometimes said to ''dominate'' (or ''eventually dominate'') the series with smaller terms. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Infinite Series In mathematics, a series is, roughly speaking, an addition of infinitely many terms, one after the other. The study of series is a major part of calculus and its generalization, mathematical analysis. Series are used in most areas of mathematics, even for studying finite structures in combinatorics through generating functions. The mathematical properties of infinite series make them widely applicable in other quantitative disciplines such as physics, computer science, statistics and finance. Among the Ancient Greeks, the idea that a potentially infinite summation could produce a finite result was considered paradoxical, most famously in Zeno's paradoxes. Nonetheless, infinite series were applied practically by Ancient Greek mathematicians including Archimedes, for instance in the quadrature of the parabola. The mathematical side of Zeno's paradoxes was resolved using the concept of a limit during the 17th century, especially through the early calculus of Isaac Newton. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
picture info	Limit Superior In mathematics, the limit inferior and limit superior of a sequence can be thought of as limiting (that is, eventual and extreme) bounds on the sequence. They can be thought of in a similar fashion for a function (see limit of a function). For a set, they are the infimum and supremum of the set's limit points, respectively. In general, when there are multiple objects around which a sequence, function, or set accumulates, the inferior and superior limits extract the smallest and largest of them; the type of object and the measure of size is context-dependent, but the notion of extreme limits is invariant. Limit inferior is also called infimum limit, limit infimum, liminf, inferior limit, lower limit, or inner limit; limit superior is also known as supremum limit, limit supremum, limsup, superior limit, upper limit, or outer limit. The limit inferior of a sequence (x_n) is denoted by \liminf_x_n\quad\text\quad \varliminf_x_n, and the limit superior of a sequence (x_n) is deno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Parseval's Formula In mathematical analysis, Parseval's identity, named after Marc-Antoine Parseval, is a fundamental result on the summability of the Fourier series of a function. The identity asserts the equality of the energy of a periodic signal (given as the integral of the squared amplitude of the signal) and the energy of its frequency domain representation (given as the sum of squares of the amplitudes). Geometrically, it is a generalized Pythagorean theorem for inner-product spaces (which can have an uncountable infinity of basis vectors). The identity asserts that the sum of squares of the Fourier coefficients of a function is equal to the integral of the square of the function, \Vert f \Vert^2_ = \frac1\int_^\pi , f(x), ^2 \, dx = \sum_^\infty , \hat f(n), ^2, where the Fourier coefficients \hat f(n) of f are given by \hat f(n) = \frac \int_^ f(x) e^ \, dx. The result holds as stated, provided f is a square-integrable function or, more generally, in ''L''''p'' space L^2 \pi, \p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Convergence Tests In mathematics, convergence tests are methods of testing for the convergence, conditional convergence, absolute convergence, interval of convergence or divergence of an infinite series \sum_^\infty a_n. List of tests Limit of the summand If the limit of the summand is undefined or nonzero, that is \lim_a_n \ne 0, then the series must diverge. In this sense, the partial sums are Cauchy only if this limit exists and is equal to zero. The test is inconclusive if the limit of the summand is zero. This is also known as the nth-term test, test for divergence, or the divergence test. Ratio test This is also known as d'Alembert's criterion. : Consider two limits \ell=\liminf_\left, \frac\ and L=\limsup_\left, \frac\. If \ell>1, the series diverges. If L 1. The case of p = 1, k = 1 yields the harmonic series, which diverges. The case of p = 2, k = 1 is the Basel problem and the series converges to \frac. In general, for p > 1, k = 1, the series is equal to the Riemann zeta funct ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]
	Direct Comparison Test In mathematics, the comparison test, sometimes called the direct comparison test to distinguish it from similar related tests (especially the limit comparison test), provides a way of deducing whether an infinite series or an improper integral converges or diverges by comparing the series or integral to one whose convergence properties are known. For series In calculus, the comparison test for series typically consists of a pair of statements about infinite series with non-negative ( real-valued) terms: * If the infinite series \sum b_n converges and 0 \le a_n \le b_n for all sufficiently large ''n'' (that is, for all n>N for some fixed value ''N''), then the infinite series \sum a_n also converges. * If the infinite series \sum b_n diverges and 0 \le b_n \le a_n for all sufficiently large ''n'', then the infinite series \sum a_n also diverges. Note that the series having larger terms is sometimes said to ''dominate'' (or ''eventually dominate'') the series with smaller terms. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu]

Proof