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数学符号说明

整理常用数学符号的读法、含义、LaTeX 命令、示例与 AI 提问思路的实用参考。

基础运算

Plus

读法
plus
LaTeX

含义

Adds two quantities.

示例

3+5=83+5=8

基础运算

Minus

读法
minus
LaTeX

含义

Subtracts one quantity from another, or marks a negative value.

示例

94=59-4=5

基础运算

Multiplication sign

读法
times
LaTeX

含义

Multiplies two quantities. In algebra, multiplication is often written with a dot or omitted.

示例

7×8=567\times 8=56

基础运算

Division sign

读法
divided by
LaTeX

含义

Divides one quantity by another nonzero quantity.

示例

12÷4=312\div 4=3

基础运算

Fraction

读法
a over b
LaTeX

含义

Represents division or a ratio with a numerator and denominator.

示例

36=12\frac{3}{6}=\frac{1}{2}

基础运算

Plus-minus

读法
plus or minus
LaTeX

含义

Indicates that both the positive and negative alternatives are being considered.

示例

10±3=13 or 710\pm 3=13\text{ or }7

基础运算

Square root

读法
square root of x
LaTeX

含义

The nonnegative value whose square is x, unless a different convention is stated.

示例

9=3\sqrt{9}=3

关系

Equals

读法
equals
LaTeX

含义

States that two expressions have the same value or represent the same object.

示例

2+3=52+3=5

关系

Not equal

读法
is not equal to
LaTeX

含义

Shows that two expressions do not have the same value.

示例

454\ne 5

关系

Approximately equal

读法
approximately equal to
LaTeX

含义

Indicates a rounded or approximate value rather than exact equality.

示例

π3.14\pi\approx 3.14

关系

Less than or equal to

读法
less than or equal to
LaTeX

含义

Allows equality while comparing two quantities.

示例

x10x\le 10

关系

Greater than or equal to

读法
greater than or equal to
LaTeX

含义

Compares two quantities while allowing equality.

示例

x0x\ge 0

关系

Proportional to

读法
is proportional to
LaTeX

含义

Shows that one quantity changes by a constant multiple of another.

示例

yxy\propto x

集合论

Empty set

读法
empty set
LaTeX

含义

The set with no elements.

示例

{1}{2}=\{1\}\cap\{2\}=\emptyset

集合论

Element of

读法
is an element of
LaTeX

含义

Shows that a value belongs to a set.

示例

3{1,2,3}3\in\{1,2,3\}

集合论

Not an element of

读法
is not an element of
LaTeX

含义

Shows that a value does not belong to a set.

示例

4{1,2,3}4\notin\{1,2,3\}

集合论

Proper subset

读法
is a proper subset of
LaTeX

含义

Usually indicates that every element of one set is in another, and the two sets are not equal.

示例

{1,2}{1,2,3}\{1,2\}\subset\{1,2,3\}

集合论

Subset or equal

读法
is a subset of or equal to
LaTeX

含义

Allows two sets to be equal while stating subset inclusion.

示例

{1,2}{1,2}\{1,2\}\subseteq\{1,2\}

集合论

Union

读法
union
LaTeX

含义

Combines all elements that are in either set.

示例

{1,2}{2,3}={1,2,3}\{1,2\}\cup\{2,3\}=\{1,2,3\}

集合论

Intersection

读法
intersection
LaTeX

含义

Keeps only the elements shared by both sets.

示例

{1,2}{2,3}={2}\{1,2\}\cap\{2,3\}=\{2\}

逻辑

Universal quantifier

读法
for all
LaTeX

含义

States that a claim applies to every object in a domain.

示例

xR, x20\forall x\in\mathbb{R},\ x^2\ge 0

逻辑

Existential quantifier

读法
there exists
LaTeX

含义

States that at least one object satisfying a condition exists.

示例

xR:x2=4\exists x\in\mathbb{R}: x^2=4

逻辑

Negation

读法
not
LaTeX

含义

Reverses the truth value of a statement.

示例

¬P\neg P

逻辑

Logical and

读法
and
LaTeX

含义

True only when both connected statements are true.

示例

PQP\land Q

逻辑

Logical or

读法
or
LaTeX

含义

True when at least one connected statement is true.

示例

PQP\lor Q

逻辑

Implication

读法
implies
LaTeX

含义

Connects a condition to a conclusion.

示例

x>2x2>4x>2\Rightarrow x^2>4

逻辑

If and only if

读法
if and only if
LaTeX

含义

States that two statements imply each other.

示例

x2=1x=±1x^2=1\Leftrightarrow x=\pm 1

数集

Natural numbers

读法
the natural numbers
LaTeX

含义

The set used for counting numbers. Whether 0 is included depends on convention.

示例

nNn\in\mathbb{N}

数集

Integers

读法
the integers
LaTeX

含义

All whole numbers, including negative values, zero, and positive values.

示例

3Z-3\in\mathbb{Z}

数集

Rational numbers

读法
the rational numbers
LaTeX

含义

Numbers expressible as a ratio of two integers with nonzero denominator.

示例

23Q\frac{2}{3}\in\mathbb{Q}

数集

Real numbers

读法
the real numbers
LaTeX

含义

Numbers represented on the continuous number line.

示例

2R\sqrt{2}\in\mathbb{R}

数集

Complex numbers

读法
the complex numbers
LaTeX

含义

Numbers of the form a+bi, where i is the imaginary unit.

示例

3+2iC3+2i\in\mathbb{C}

数集

Pi

读法
pi
LaTeX

含义

The constant ratio of a circle's circumference to its diameter.

示例

A=πr2A=\pi r^2

微积分与分析

Infinity

读法
infinity
LaTeX

含义

A symbol for unbounded growth or an unending process, not an ordinary real number.

示例

limx1x=0\lim_{x\to\infty}\frac{1}{x}=0

微积分与分析

Summation

读法
sum
LaTeX

含义

Adds a sequence of terms over an index range.

示例

k=14k2=30\sum_{k=1}^{4}k^2=30

微积分与分析

Product notation

读法
product
LaTeX

含义

Multiplies a sequence of terms over an index range.

示例

k=14k=24\prod_{k=1}^{4}k=24

微积分与分析

Integral

读法
integral
LaTeX

含义

Represents accumulation, signed area, or an antiderivative depending on context.

示例

01x2dx=13\int_0^1 x^2\,dx=\frac{1}{3}

微积分与分析

Partial derivative symbol

读法
partial
LaTeX

含义

Used when differentiating a multivariable function with respect to one variable.

示例

fx\frac{\partial f}{\partial x}

微积分与分析

Nabla

读法
nabla
LaTeX

含义

Used for gradient, divergence, curl, and related vector-calculus operations.

示例

f\nabla f

代数

Matrix

读法
matrix
LaTeX

含义

A rectangular arrangement of entries used to represent linear maps, systems, and data.

示例

[1234]\begin{bmatrix}1&2\\3&4\end{bmatrix}

代数

Transpose

读法
A transpose
LaTeX

含义

Swaps rows and columns of a matrix.

示例

[1234]T=[1324]\begin{bmatrix}1&2\\3&4\end{bmatrix}^T=\begin{bmatrix}1&3\\2&4\end{bmatrix}

代数

Inverse matrix

读法
A inverse
LaTeX

含义

A matrix that multiplies with A to produce the identity matrix, when it exists.

示例

AA1=IAA^{-1}=I

代数

Determinant

读法
determinant of A
LaTeX

含义

A scalar value that captures scaling, orientation, and invertibility information of a square matrix.

示例

det[abcd]=adbc\det\begin{bmatrix}a&b\\c&d\end{bmatrix}=ad-bc

几何

Angle

读法
angle
LaTeX

含义

Represents an angle formed by two rays or segments.

示例

ABC=60\angle ABC=60^\circ

几何

Degree

读法
degrees
LaTeX

含义

A unit for measuring angles, where a full turn is 360 degrees.

示例

9090^\circ

几何

Perpendicular

读法
is perpendicular to
LaTeX

含义

Shows that two lines or vectors meet at a right angle.

示例

ABCDAB\perp CD

几何

Parallel

读法
is parallel to
LaTeX

含义

Shows that two lines or vectors have the same direction and do not meet in a plane.

示例

ABCDAB\parallel CD

括号与分隔符

Absolute value

读法
absolute value of x
LaTeX

含义

The distance of a number from zero on the number line.

示例

3=3|-3|=3

括号与分隔符

Floor

读法
floor of x
LaTeX

含义

The greatest integer less than or equal to x.

示例

3.8=3\lfloor 3.8\rfloor=3

括号与分隔符

Ceiling

读法
ceiling of x
LaTeX

含义

The smallest integer greater than or equal to x.

示例

3.2=4\lceil 3.2\rceil=4

缩写与标记惯例

End of proof

读法
QED
LaTeX

含义

Marks the end of a proof. Some texts use Q.E.D. or a filled square.

示例

x=1.\therefore x=1.\quad\square

缩写与标记惯例

Therefore

读法
therefore
LaTeX

含义

Introduces a conclusion that follows from previous statements.

示例

a=b, b=c a=ca=b,\ b=c\ \therefore a=c

缩写与标记惯例

Because

读法
because
LaTeX

含义

Introduces a reason or supporting statement.

示例

x>0\because x>0

延伸参考

以下链接仅作为延伸阅读资料。本页说明与示例按网站目的重新编写。