常用数学符号英文对照.docx

常用数学符号英文对照.docx

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常用数学符号英文对照

常用数学符号英文对照

Basicmathsymbols

Symbol

SymbolName

Meaning/definition

Example

=

equalssign

equality

5=2+3

5isequalto2+3

≠

notequalsign

inequality

5≠4

5isnotequalto4

≈

approximatelyequal

approximation

sin（0.01）≈0.01,

x ≈ y means x isapproximatelyequalto y

>

strictinequality

greaterthan

5>4

5isgreaterthan4

<

strictinequality

lessthan

4<5

4islessthan5

≥

inequality

greaterthanorequalto

5≥4,

x ≥ y means x isgreaterthanorequalto y

≤

inequality

lessthanorequalto

4≤5,

x≤y means x isgreaterthanorequalto y

（）

parentheses

calculateexpressioninsidefirst

2×（3+5）=16

[]

brackets

calculateexpressioninsidefirst

[（1+2）×（1+5）]=18

+

plussign

addition

1+1=2

−

minussign

subtraction

2−1=1

±

plus-minus

bothplusandminusoperations

3±5=8and-2

±

minus-plus

bothminusandplusoperations

3±5=-2and8

*

asterisk

multiplication

2*3=6

×

timessign

multiplication

2×3=6

·

multiplicationdot

multiplication

2·3=6

÷

divisionsign/obelus

division

6÷2=3

/

divisionslash

division

6/2=3

–

horizontalline

division/fraction

mod

modulo

remaindercalculation

7mod2=1

.

period

decimalpoint,decimalseparator

2.56=2+56/100

ab

power

exponent

23 =8

a^b

caret

exponent

2^3 =8

√a

squareroot

√a · √a  =a

√9 =±3

3√a

cuberoot

3√a · 3√a  · 3√a  =a

3√8 =2

4√a

fourthroot

4√a · 4√a  · 4√a  · 4√a  =a

4√16 =±2

n√a

n-throot（radical）

for n=3, n√8 =2

%

percent

1%=1/100

10%×30=3

‰

per-mille

1‰=1/1000=0.1%

10‰×30=0.3

ppm

per-million

1ppm=1/1000000

10ppm×30=0.0003

ppb

per-billion

1ppb=1/1000000000

10ppb×30=3×10-7

ppt

per-trillion

1ppt=10-12

10ppt×30=3×10-10

Geometrysymbols

Symbol

SymbolName

Meaning/definition

Example

∠

angle

formedbytworays

∠ABC=30°

measuredangle

ABC=30°

sphericalangle

AOB=30°

∟

rightangle

=90°

α=90°

°

degree

1turn=360°

α=60°

deg

degree

1turn=360deg

α=60deg

′

prime

arcminute,1°=60′

α=60°59′

″

doubleprime

arcsecond,1′=60″

α=60°59′59″

line

infiniteline

AB

linesegment

linefrompointAtopointB

ray

linethatstartfrompointA

arc

arcfrompointAtopointB

 =60°

⊥

perpendicular

perpendicularlines（90°angle）

AC ⊥ BC

||

parallel

parallellines

AB || CD

≅

congruentto

equivalenceofgeometricshapesandsize

∆ABC≅∆XYZ

~

similarity

sameshapes,notsamesize

∆ABC~∆XYZ

Δ

triangle

triangleshape

ΔABC≅ΔBCD

|x-y|

distance

distancebetweenpointsxandy

| x-y |=5

π

piconstant

π =3.141592654...

istheratiobetweenthecircumferenceanddiameterofacircle

c = π·d =2·π·r

rad

radians

radiansangleunit

360°=2πrad

c

radians

radiansangleunit

360°=2π c

grad

gradians/gons

gradsangleunit

360°=400grad

g

gradians/gons

gradsangleunit

360°=400 g

Algebrasymbols

Symbol

SymbolName

Meaning/definition

Example

x

xvariable

unknownvaluetofind

when2x =4,then x =2

≡

equivalence

identicalto

≜

equalbydefinition

equalbydefinition

:

=

equalbydefinition

equalbydefinition

~

approximatelyequal

weakapproximation

11~10

≈

approximatelyequal

approximation

sin（0.01）≈0.01

∝

proportionalto

proportionalto

y ∝ x when y = kx,k constant

∞

lemniscate

infinitysymbol

≪

muchlessthan

muchlessthan

1≪1000000

≫

muchgreaterthan

muchgreaterthan

1000000≫1

（）

parentheses

calculateexpressioninsidefirst

2*（3+5）=16

[]

brackets

calculateexpressioninsidefirst

[（1+2）*（1+5）]=18

{}

braces

set

⌊x⌋

floorbrackets

roundsnumbertolowerinteger

⌊4.3⌋=4

⌈x⌉

ceilingbrackets

roundsnumbertoupperinteger

⌈4.3⌉=5

x!

exclamationmark

factorial

4!

=1*2*3*4=24

| x |

singleverticalbar

absolutevalue

|-5|=5

f （x）

functionofx

mapsvaluesofxtof（x）

f （x）=3x+5

（f ∘ g）

functioncomposition

（f ∘ g）（x）= f （g（x））

f （x）=3x,g（x）=x-1⇒（f ∘ g）（x）=3（x-1）

（a,b）

openinterval

（a,b）={x | a < x < b}

x∈（2,6）

[a,b]

closedinterval

[a,b]={x | a ≤ x ≤ b}

x ∈[2,6]

∆

delta

change/difference

∆t = t1 - t0

∆

discriminant

Δ= b2 -4ac

∑

sigma

summation-sumofallvaluesinrangeofseries

∑ xi=x1+x2+...+xn

∑∑

sigma

doublesummation

∏

capitalpi

product-productofallvaluesinrangeofseries

∏ xi=x1∙x2∙...∙xn

e

econstant /Euler'snumber

e =2.718281828...

e =lim（1+1/x）x , x→∞

γ

Euler-Mascheroni constant

γ=0.527721566...

φ

goldenratio

goldenratioconstant

π

piconstant

π =3.141592654...

istheratiobetweenthecircumferenceanddiameterofacircle

c = π·d =2·π·r

LinearAlgebraSymbols

Symbol

SymbolName

Meaning/definition

Examp