Name: summation notation for sequences
Uploaded: 2025-11-26T05:43:54.000Z
Duration: 1 min 25 s
Channel: JoVE

La notation de sommation est utilisée pour écrire des sommes de termes qui suivent un modèle.La lettre grecque sigma signifie sommation. Il signale l’ajout de valeurs d’un terme de début à un terme de fin.Le nombre sous le sigma indique où commencer la somme, et le nombre ci-dessus indique où s’arrêter. Une sommation est directement liée à des séquences, puisque chaque somme est formée par l’addition de termes consécutifs d’une séquence.Chaque terme de la somme est formé en insérant la valeur de l’indice dans une expression donnée.Imaginez maintenant qu’un propriétaire suive la production d’électricité à partir d’un panneau solaire pendant les dix premiers jours du printemps.Comme la lumière du jour varie, la production quotidienne varie, avec des sorties étiquetées E1 à E10.Au lieu d’écrire E1 plus E2 plus E3 et de continuer jusqu’à E10, le total est exprimé à l’aide d’une sommation compacte.Cela représente l’ajout des sorties quotidiennes indépendamment des variations météorologiques.L’extension de cette somme à trois cent soixante-cinq jours fournit une production solaire annuelle.La comparaison de la production solaire annuelle avec les besoins en électricité des ménages montre quelle part des besoins énergétiques de la maison est couverte par l’énergie solaire.

notation de sommation

Summation Notation

La notation sigma, &#233;galement appel&#233;e notation de sommation, offre une m&#233;thode concise pour repr&#233;senter la somme d&#8217;une suite de termes suivant un motif r&#233;gulier. Elle utilise la lettre grecque majuscule sigma (&#8721;)&#160;; une expression typique est&#160;:<figure class='image image-style-align-center image_resized' style='display:table;margin-left:auto;margin-right:auto;width:100%;'><img style='aspect-ratio:300/15;' src='https://cloudfront.jove.com/files/ftp_upload/41038/41038_Equation_1_editor_41038.svg' alt='41038_Equation_1.svg' /></figure>Dans cette &#233;criture, k est l&#8217;indice de sommation ; 1 est la valeur initiale et n est la valeur finale. Le terme a_k d&#233;signe le terme g&#233;n&#233;ral de la suite.Par exemple, la suite croissante 5, 7, 9, &#8230;, 23 sur 10 termes peut &#234;tre exprim&#233;e comme suit :<figure class='image image-style-align-center image_resized' style='display:table;margin-left:auto;margin-right:auto;width:100%;'><img style='aspect-ratio:300/17;' src='https://cloudfront.jove.com/files/ftp_upload/41038/41038_Equation_2_editor_41038.svg' alt='41038_Equation_2.svg' /></figure>Cela simplifie la repr&#233;sentation de tels motifs sous une forme compacte.La notation sigma ob&#233;it &#224; des propri&#233;t&#233;s alg&#233;briques utiles qui facilitent la simplification et la manipulation des sommes&#160;:<figure class='image image-style-align-center image_resized' style='display:table;margin-left:auto;margin-right:auto;width:86.91%;'><img style='aspect-ratio:300/15;' src='https://cloudfront.jove.com/files/ftp_upload/41038/41038_Equation_3_editor_41038.svg' alt='41038_Equation_3.svg' /></figure><figure class='image image-style-align-center image_resized' style='display:table;margin-left:auto;margin-right:auto;width:86.91%;'><img style='aspect-ratio:300/15;' src='https://cloudfront.jove.com/files/ftp_upload/41038/41038_Equation_4_editor_41038.svg' alt='41038_Equation_4.svg' /></figure><figure class='image image-style-align-center image_resized' style='display:table;margin-left:auto;margin-right:auto;width:86.91%;'><img style='aspect-ratio:300/15;' src='https://cloudfront.jove.com/files/ftp_upload/41038/41038_Equation_5_editor_41038.svg' alt='41038_Equation_5.svg' /></figure>Ces propri&#233;t&#233;s reposent sur les lois associatives et distributives des nombres r&#233;els, ce qui permet une &#233;valuation et une transformation efficaces des sommes. De plus, la notation sigma s&#8217;adapte &#224; des indices de d&#233;part et &#224; des expressions vari&#233;es, &#233;largissant ainsi son champ d&#8217;application aux contextes math&#233;matiques th&#233;oriques et appliqu&#233;s, tels que l&#8217;&#233;valuation de s&#233;ries, la mod&#233;lisation de courbes de croissance ou le calcul de totaux cumul&#233;s dans des situations r&#233;elles.

Notation de sommation

La notation sigma, &#233;galement appel&#233;e notation de sommation, offre une m&#233;thode concise pour repr&#233;senter la somme d&#8217;une suite de ...

Education

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JoVE Core

Math Fundamentals

Fondamentaux des mathématiques

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Introduction to Sequences and Series

Introduction aux suites et séries

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

summation notation for sequences

Sigma notation, also called summation notation, gives a short way to write the sum of a sequence of terms that follow a regular pattern. It uses the uppercase Greek letter sigma, ∑, to show that terms are being added together.

A typical sigma expression includes an index of summation. The index starts at a lower value, such as 1, and ends at an upper value, such as n. The term a_k represents the general term in the sequence, where k changes across the stated range.

For example, the increasing sequence 5, 7, 9, ..., 23 over 10 terms can be written with sigma notation. This makes the pattern easier to show in a compact form. Sigma notation also follows useful algebraic properties. These properties come from the associative and distributive laws of real numbers, which help simplify and manipulate sums.

Sigma notation can also use different starting indices and expressions. That flexibility makes it useful in both theory and application. It can help evaluate series, model growth patterns, and calculate cumulative totals in real-world settings.

Summation Notation for Sequences

sequences

Recursive Sequences and Partial Sums

Sequences are ordered lists of numbers that follow a rule or pattern. Each number in the list is called a term. Terms are often written as a1, a2, a3, and so on, where the subscript shows the position in the sequence. When the pattern is clear, dots may be used to show that the list continues. A sequence can also be viewed as a function. Its domain is the set of natural numbers, and each natural number maps to one term in the list. This view is useful when a sequence is defined explicitly or...

summation notation

Sigma notation, also called summation notation, gives a short way to write the sum of a sequence of terms that follow a regular pattern. It uses the uppercase Greek letter sigma, ∑, to show that terms are being added together. A typical sigma expression includes an index of summation. The index starts at a lower value, such as 1, and ends at an upper value, such as n. The term a_k represents the general term in the sequence, where k changes across the stated range. For example, the increasing...

arithmetic sequences

Arithmetic Sequence Formulas and Partial Sums

Arithmetic sequences follow a regular number pattern. Each term is found by adding the same value, called the common difference, to the term before it. This steady change makes the sequence easy to study and predict. The nth-term formula helps find any term in the sequence without listing every earlier number. In this formula, a n is the nth term, a is the first term, d is the common difference, and n shows the term position. It gives a direct way to calculate a specific value from the pattern.

geometric sequences

Infinite Geometric Series and Decay

Infinite geometric series describe values that shrink by the same factor each step. Each new term is found by multiplying the previous term by a fixed common ratio. This pattern is useful for modeling gradual loss, such as energy dissipation or a drop in amplitude over time. When the common ratio has a magnitude less than one, the terms keep getting smaller. In that case, the total of the series approaches a definite number instead of growing without bound or changing back and forth. This is...

mathematical induction

Proving Number Patterns with Induction

Mathematical induction is a proof method for statements about natural numbers. It is often used to test whether a pattern really works for every number in a sequence. A common example is the sum of the first n natural numbers, where the formula seems to hold as more terms are added. The proof begins with a base case. In this step, the formula is checked at the first value, usually n = 1. Substituting 1 into both sides shows that the equality is true, so the base case holds. Next comes the...

the binomial theorem

Expanding Binomials with the Binomial Theorem

The Binomial Theorem gives a clear method for expanding binomial expressions raised to a power. It applies to binomials of the form (a + b)^n, where a and b are variables or constants that represent algebraic expressions, and n is a non-negative integer. Each term in the expansion follows a fixed pattern. The binomial coefficient in each term is found using factorials. The exponent of a decreases from n to 0, while the exponent of b increases from 0 to n. The theorem also helps students...

binomial expansion using pascal's triangle

binomial-expansion-using-pascal-s-triangle

Pascal’s Triangle for Binomial Coefficients

Pascal’s Triangle helps organize the coefficients in a binomial expansion. A binomial is an expression with two terms, such as (a + b), and raising it to a power creates a predictable pattern of terms. The triangle is built row by row. The top row, called the zeroth row, matches (a + b)0. Each new row gives the coefficients for the next power of the binomial, so the sixth row, 1, 5, 10, 10, 5, 1, gives the coefficients for (a + b)5. Each row begins and ends with 1. Every number inside the...

key terms and concepts

Learn how sigma notation writes sequence sums with an index, general term, and useful algebraic properties for simplifying expressions and modeling totals.

Summation Notation for Sequences | JoVE K12

The JoVE Math Fundamentals collection is designed to build a deep and comprehensive understanding of essential mathematics. Covering the foundations of algebra, geometry, trigonometry, and analytic reasoning, this course establishes a strong base for future studies. The collection connects core mathematical concepts with real-world practice, equipping learners to solve complex problems, master problem-solving skills, and apply abstract ideas.

math fundamentals

Summation Notation for Sequences

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