obelus (2024)

FAQs

Why is the obelus not used? ›

Because it's ambiguous. In some parts of Northern Europe, the same symbol occasionally denoted subtraction. Its use was never particularly widespread in mathematics. It somehow caught on as notation used in teaching arithmetic in English-speaking countries.

In mathematics

The form of the obelus as a horizontal line with a dot above and a dot below, ÷, was first used as a symbol for division by the Swiss mathematician Johann Rahn in his book Teutsche Algebra in 1659. This gave rise to the modern mathematical symbol ÷, used in anglophone countries as a division sign.

In math, an obelus is a symbol that means "divided by," while in an ancient text it's an editorial mark on a line or word that is incorrect or doubtful.

The solidus (or slash, slant, shilling mark, or virgule) is a versatile symbol that has mathematical as well as textual functions. Use a solidus to express a quotient in text when you do not need to use a displayed equation. lifetime by the expression 1/t = 1/t_B + 2 S/D.

PEMDAS stands for P- Parentheses, E- Exponents, M- Multiplication, D- Division, A- Addition, and S- Subtraction.

Caret is the name used familiarly for the character ^ (the circumflex and a circumflex accent) provided on most QWERTY keyboards by typing ⇧ Shift + 6 .

In Microsoft Windows, this division sign is produced with Alt+0247 (or 246 with no zero) on the number pad, or by pressing Alt Gr + ⇧ Shift + + when an appropriate keyboard layout is in use. In classic Mac OS and macOS, it is produced with ⌥ Option + / .

⊙ Hadamard Product

This circle-dot symbol can mean a few different things, depending on context. Typically in machine learning literature, it refers to the Hadamard product (component-wise multiplication for matrices).

⨂ is the Kronecker product of two matrices. In this post I used the Kronecker product to understand the model matrices in mixed effects models. A∗=AH=ˉAT is the Hermitian or conjugate transpose of a matrix A.

Muhammad ibn Musa Al-Khwarizmi: The Father of Algebra | Lowell Milken Center.

What does (;) mean in math? ›

A semicolon represented by ';' usually separates parameters and variables from one another. Parameters are defined in functions, for example, f (x1, x2, x3 ; y1, y2, y3) = x1 + x2 - x3 * y1 / y2 + y3. A semicolon may also be used to separate algebraic expressions, like ax + by = 5m; cx + dy = 6n.

The infinity symbol, a figure eight on its side, variously signifies the concept of limitlessness or eternity, especially as used notationally in mathematics and metaphorically with respect to love.

The nabla is used in vector calculus as part of three distinct differential operators: the gradient (∇), the divergence (∇⋅), and the curl (∇×). The last of these uses the cross product and thus makes sense only in three dimensions; the first two are fully general.

The symbol for parallel is ∥. The symbol for angle is ∠. The symbol for perpendicular is ⊥. The symbol for congruent is ≅.

The not-element-of symbol looks like the element-of symbol except that a forward slash runs through it (∉). The not-element-of symbol is read as "is not an element of," "is not a member of," "is not in" or "does not belong to." For example, the following expression indicates that 7 is not an element of set A: 7 ∉ A.

Use the multiplication sign (×), not the letter x, to indicate the mathematical operation.

In mathematics

The ISO 80000-2 standard for mathematical notation recommends only the solidus / or "fraction bar" for division, or the "colon" : for ratios; it says that the ÷ sign "should not be used" for division.

The dagger symbol originated from a variant of the obelus, originally depicted by a plain line − or a line with one or two dots ÷. It represented an iron roasting spit, a dart, or the sharp end of a javelin, symbolizing the skewering or cutting out of dubious matter.

The obelus (÷) was first used as a division symbol by Johann Rahn (or Rhonius) (1622-1676) in 1659 in Teutsche Algebra (Cajori vol. 2, page 211).