<Li> Symbols based on Hebrew or Greek letters e.g. ב, א, δ, Δ, π, Π, σ, Σ, Φ . Note: symbols resembling Λ are grouped with "V" under Latin letters . </Li> <Li> Variations: Usage in languages written right - to - left </Li> <Table> <Tr> <Th> Symbol in HTML </Th> <Th> Symbol in TeX </Th> <Th> Name </Th> <Th> Explanation </Th> <Th> Examples </Th> </Tr> <Tr> <Th> Read as </Th> </Tr> <Tr> <Th> Category </Th> </Tr> <Tr> <Td> + </Td> <Td> + (\ displaystyle +) </Td> <Td> addition plus; add arithmetic </Td> <Td> 4 + 6 means the sum of 4 and 6 . </Td> <Td> 2 + 7 = 9 </Td> </Tr> <Tr> <Td> disjoint union the disjoint union of...and...set theory </Td> <Td> A + A means the disjoint union of sets A and A . </Td> <Td> A = (3, 4, 5, 6) ∧ A = (7, 8, 9, 10) ⇒ A + A = ((3, 1), (4, 1), (5, 1), (6, 1), (7, 2), (8, 2), (9, 2), (10, 2)) </Td> </Tr> <Tr> <Td> − </Td> <Td> − (\ displaystyle -) </Td> <Td> subtraction minus; take; subtract arithmetic </Td> <Td> 36 − 11 means the subtraction of 11 from 36 . </Td> <Td> 36 − 11 = 25 </Td> </Tr> <Tr> <Td> negative sign negative; minus; the opposite of arithmetic </Td> <Td> − 3 means the additive inverse of the number 3 . </Td> <Td> − (− 5) = 5 </Td> </Tr> <Tr> <Td> set - theoretic complement minus; without set theory </Td> <Td> A − B means the set that contains all the elements of A that are not in B . (∖ can also be used for set - theoretic complement as described below .) </Td> <Td> (1, 2, 4) − (1, 3, 4) = (2) </Td> </Tr> <Tr> <Td> ± </Td> <Td> ± (\ displaystyle \ pm) \ pm </Td> <Td> plus - minus plus or minus arithmetic </Td> <Td> 6 ± 3 means both 6 + 3 and 6 − 3 . </Td> <Td> The equation x = 5 ± √ 4, has two solutions, x = 7 and x = 3 . </Td> </Tr> <Tr> <Td> plus - minus plus or minus measurement </Td> <Td> 10 ± 2 or equivalently 10 ± 20% means the range from 10 − 2 to 10 + 2 . </Td> <Td> If a = 100 ± 1 mm, then a ≥ 99 mm and a ≤ 101 mm . </Td> </Tr> <Tr> <Td> ∓ </Td> <Td> ∓ (\ displaystyle \ mp) \ mp </Td> <Td> minus - plus minus or plus arithmetic </Td> <Td> 6 ± (3 ∓ 5) means 6 + (3 − 5) and 6 − (3 + 5). </Td> <Td> cos (x ± y) = cos (x) cos (y) ∓ sin (x) sin (y). </Td> </Tr> <Tr> <Td> × ⋅ </Td> <Td> × (\ displaystyle \ times) \ times ⋅ (\ displaystyle \ cdot) \ cdot </Td> <Td> multiplication times; multiplied by arithmetic </Td> <Td> 3 × 4 or 3 ⋅ 4 means the multiplication of 3 by 4 . </Td> <Td> 7 ⋅ 8 = 56 </Td> </Tr> <Tr> <Td> dot product scalar product dot linear algebra vector algebra </Td> <Td> u ⋅ v means the dot product of vectors u and v </Td> <Td> (1, 2, 5) ⋅ (3, 4, − 1) = 6 </Td> </Tr> <Tr> <Td> cross product vector product cross linear algebra vector algebra </Td> <Td> u × v means the cross product of vectors u and v </Td> <Td> (1, 2, 5) × (3, 4, − 1) = <Table> <Tr> <Td> i </Td> <Td> j </Td> <Td> k </Td> </Tr> <Tr> <Td> </Td> <Td> </Td> <Td> 5 </Td> </Tr> <Tr> <Td> </Td> <Td> </Td> <Td> − 1 </Td> </Tr> </Table> = (− 22, 16, − 2) </Td> </Tr> <Tr> <Td> placeholder (silent) functional analysis </Td> <Td> A means a placeholder for an argument of a function . Indicates the functional nature of an expression without assigning a specific symbol for an argument . </Td> <Td> </Td> </Tr> <Tr> <Td> ÷ ⁄ </Td> <Td> ÷ (\ displaystyle \ div) \ div / (\ displaystyle /) </Td> <Td> division (Obelus) divided by; over arithmetic </Td> <Td> 6 ÷ 3 or 6 ⁄ 3 means the division of 6 by 3 . </Td> <Td> 2 ÷ 4 = 0.5 12 ⁄ 4 = 3 </Td> </Tr> <Tr> <Td> quotient group mod group theory </Td> <Td> G / H means the quotient of group G modulo its subgroup H . </Td> <Td> (0, a, 2a, b, b + a, b + 2a) / (0, b) = ((0, b), (a, b + a), (2a, b + 2a)) </Td> </Tr> <Tr> <Td> quotient set mod set theory </Td> <Td> A / ~ means the set of all ~ equivalence classes in A . </Td> <Td> If we define ~ by x ~ y ⇔ x − y ∈ Z, then R / ~ = (x + n: n ∈ Z, x ∈ (0, 1)). </Td> </Tr> <Tr> <Td> √ </Td> <Td> √ (\ displaystyle \ surd) \ surd x (\ displaystyle (\ sqrt (x))) \ sqrt (x) </Td> <Td> square root (radical symbol) the (principal) square root of real numbers </Td> <Td> √ x means the nonnegative number whose square is x . </Td> <Td> √ 4 = 2 </Td> </Tr> <Tr> <Td> complex square root the (complex) square root of complex numbers </Td> <Td> If z = r exp (iφ) is represented in polar coordinates with − π <φ ≤ π, then √ z = √ r exp (iφ / 2). </Td> <Td> √ − 1 = i </Td> </Tr> <Tr> <Td> ∑ </Td> <Td> ∑ (\ displaystyle \ sum) \ sum </Td> <Td> summation sum over...from...to...of calculus </Td> <Td> ∑ k = 1 n a k (\ displaystyle \ sum _ (k = 1) ^ (n) (a_ (k))) means a 1 + a 2 + ⋯ + a n (\ displaystyle a_ (1) + a_ (2) + \ cdots + a_ (n)). </Td> <Td> ∑ k = 1 4 k 2 = 1 2 + 2 2 + 3 2 + 4 2 = 1 + 4 + 9 + 16 = 30 (\ displaystyle \ sum _ (k = 1) ^ (4) (k ^ (2)) = 1 ^ (2) + 2 ^ (2) + 3 ^ (2) + 4 ^ (2) = 1 + 4 + 9 + 16 = 30) </Td> </Tr> <Tr> <Td> ∫ </Td> <Td> ∫ (\ displaystyle \ int) \ int </Td> <Td> indefinite integral or antiderivative indefinite integral of - OR - the antiderivative of calculus </Td> <Td> ∫ f (x) dx means a function whose derivative is f . </Td> <Td> ∫ x 2 d x = x 3 3 + C (\ displaystyle \ int x ^ (2) dx = (\ frac (x ^ (3)) (3)) + C) </Td> </Tr> <Tr> <Td> definite integral integral from...to...of...with respect to calculus </Td> <Td> ∫ b a f (x) dx means the signed area between the x-axis and the graph of the function f between x = a and x = b . </Td> <Td> ∫ b a x dx = b − a / 3 </Td> </Tr> <Tr> <Td> line integral line / path / curve / integral of...along...calculus </Td> <Td> ∫ C f ds means the integral of f along the curve C, ∫ b a f (r (t)) r' (t) dt, where r is a parametrization of C. (If the curve is closed, the symbol ∮ may be used instead, as described below .) </Td> <Td> </Td> </Tr> <Tr> <Td> ∮ </Td> <Td> ∮ (\ displaystyle \ oint) \ oint </Td> <Td> Contour integral; closed line integral contour integral of calculus </Td> <Td> Similar to the integral, but used to denote a single integration over a closed curve or loop . It is sometimes used in physics texts involving equations regarding Gauss's Law, and while these formulas involve a closed surface integral, the representations describe only the first integration of the volume over the enclosing surface . Instances where the latter requires simultaneous double integration, the symbol ∮∮ would be more appropriate . A third related symbol is the closed volume integral, denoted by the symbol ∮∮∮ . <P> The contour integral can also frequently be found with a subscript capital letter C, ∮, denoting that a closed loop integral is, in fact, around a contour C, or sometimes dually appropriately, a circle C. In representations of Gauss's Law, a subscript capital S, ∮, is used to denote that the integration is over a closed surface . </P> </Td> <Td> If C is a Jordan curve about 0, then ∮ 1 / z dz = 2πi . </Td> </Tr> <Tr> <Td>... ⋯ ⋮ ⋰ ⋱ </Td> <Td>... (\ displaystyle \ ldots) \ ldots ⋯ (\ displaystyle \ cdots) \ cdots ⋮ (\ displaystyle \ vdots) \ vdots ⋱ (\ displaystyle \ ddots) \ ddots </Td> <Td> ellipsis and so forth everywhere </Td> <Td> Indicates omitted values from a pattern . </Td> <Td> 1 / 2 + 1 / 4 + 1 / 8 + 1 / 16 + ⋯ = 1 </Td> </Tr> <Tr> <Td> ∴ </Td> <Td> ∴ (\ displaystyle \ therefore) \ therefore </Td> <Td> therefore therefore; so; hence everywhere </Td> <Td> Sometimes used in proofs before logical consequences . </Td> <Td> All humans are mortal . Socrates is a human . ∴ Socrates is mortal . </Td> </Tr> <Tr> <Td> ∵ </Td> <Td> ∵ (\ displaystyle \ because) \ because </Td> <Td> because because; since everywhere </Td> <Td> Sometimes used in proofs before reasoning . </Td> <Td> 11 is prime ∵ it has no positive integer factors other than itself and one . </Td> </Tr> <Tr> <Td>! </Td> <Td>! (\ displaystyle!) </Td> <Td> factorial factorial combinatorics </Td> <Td> n! means the product 1 × 2 ×...× n . </Td> <Td> 4! = 1 × 2 × 3 × 4 = 24 (\ displaystyle 4! = 1 \ times 2 \ times 3 \ times 4 = 24) </Td> </Tr> <Tr> <Td> logical negation not propositional logic </Td> <Td> The statement! A is true if and only if A is false . A slash placed through another operator is the same as "!" placed in front . (The symbol! is primarily from computer science . It is avoided in mathematical texts, where the notation ¬ A is preferred .) </Td> <Td>! (! A) ⇔ A x ≠ y ⇔! (x = y) </Td> </Tr> <Tr> <Td> ¬ _̃ </Td> <Td> ¬ (\ displaystyle \ neg) \ neg ∼ (\ displaystyle \ sim) </Td> <Td> logical negation not propositional logic </Td> <Td> The statement ¬ A is true if and only if A is false . A slash placed through another operator is the same as "¬" placed in front . (The symbol ~ has many other uses, so ¬ or the slash notation is preferred . Computer scientists will often use! but this is avoided in mathematical texts .) </Td> <Td> ¬ (¬ A) ⇔ A x ≠ y ⇔ ¬ (x = y) </Td> </Tr> <Tr> <Td> ∝ </Td> <Td> ∝ (\ displaystyle \ propto) \ propto </Td> <Td> proportionality is proportional to; varies as everywhere </Td> <Td> y ∝ x means that y = kx for some constant k . </Td> <Td> if y = 2x, then y ∝ x . </Td> </Tr> <Tr> <Td> ∞ </Td> <Td> ∞ (\ displaystyle \ infty) \ infty </Td> <Td> infinity infinity numbers </Td> <Td> ∞ is an element of the extended number line that is greater than all real numbers; it often occurs in limits . </Td> <Td> lim x → 0 1 x = ∞ (\ displaystyle \ lim _ (x \ to 0) (\ frac (1) (x)) = \ infty) </Td> </Tr> <Tr> <Td> ∎ ▮ ‣ </Td> <Td> ◼ (\ displaystyle \ blacksquare) \ blacksquare ◻ (\ displaystyle \ Box) \ Box ▸ (\ displaystyle \ blacktriangleright) \ blacktriangleright </Td> <Td> end of proof QED; tombstone; Halmos finality symbol everywhere </Td> <Td> Used to mark the end of a proof . (May also be written Q.E.D.) </Td> <Td> </Td> </Tr> </Table> <Tr> <Th> Symbol in HTML </Th> <Th> Symbol in TeX </Th> <Th> Name </Th> <Th> Explanation </Th> <Th> Examples </Th> </Tr>

What does the e symbol mean in maths