# 英文数、符号、公式、图形表达

Reading of Numbers, Signs and Formulas

一、 Numbers Complex numbers : real ～ ,imaginary ～; rational ～, irrational ～; interger ～, decimals (recurring and terminating) or fractions (proper and improper); 1.Decimals ‥ 0.37 (zero) point three seven , three seven recurring (zero) point three seven repetend three seven 0: reads [ou] , zero, or nought. 2.Fractions Generally: 8

2 3

eight and two over three two thirds two divided by three

Specially:

1/2 a[one] half 1/3 a[one] third 1/4 a[one] quarter

Percent [Per Cent] and Permille [Per mille] 25% twenty five percent 25‰ twenty five permille 3. Prefixs Prefix tera symbol T value chinese name 垓，千京，兆兆

1

10

12

giga mega kilo hecto deca(deka) dici centi milli micro nano pico feto atto 二、Signs

G M k h da d c m

?

10 10 10 10 10

10

3

9

京，千兆 兆 千 百 十

6

2

?1

分 厘 毫 微 纤，纳 沙，毫纤，皮 尘，毫沙，飞 渺，毫尘，阿

10

?2

10 10 10 10 10 10

?3

?6

n p f a

?9

? 12

? 15

? 18

1.Equality and Inequality ＝ be equal to equals ≡ be identically equal to be identical to [with] be equivalent to ≈ be approximately equal to, approximately equals △ be corresponding to

2

≠ be not equal to does not equal

＜ be less than ＞ be greater than ? be less than or equal to ? be greater than or equal to 《 be far[much] less than 》 be far[much] greater than

?

?

be in direct proportion to

1 b

a ?

be in inverse proportion to

2. Positive and negative etc. ＋: positive [plus] －: negative [minus] max f (x): maximum value of min f (x): f (x) ±: plus or minus positive or negative

minimum value of f (x)

a : a sub n

n

∞: Infinity

?

: to tend to, to approach

∵ because ∴ therefore ∥ be parallel to ⊥ be perpendicular 0oC: zero degree centigrade [Celsius] 32oF:thirty two degree Fahrenheit

3

6’ six minutes, six feet. 6’’ six seconds, six inches ∠A: angle A. 3. Grouping ( ): round brackets, Parentheses [ Parenthesis 单数 ]

(a+b): open [left] round bracket a plus b close [right] round bracket. [ ]: square brackets.

｛ ｝: Braces. 〈 〉: Angle brackets a∈A: a is a member of set A. A B: A is a subset of B. A is contained in B. A∪B: union of sets A and B. A∩B: intersection of sets A and B. 4. Operation ＋: plus －:minus ×:times ÷:over [divided by] 和 sum 差 difference 积 product

A

商 quotient

余数 remainder

: absolute value of A

n!: n factorial

?s

n ?1 ?

5

n

summation of s sub n from n equals one to five Product of a sub n from n equals one to infinity

n

?a

n ?1

n

lim s the limit of S sub n as n tends to infinity (approaches infinity, gets

n? ?

4

arbitrarily large) A×B: vector product of A and B. A·B: scalar product of A and B. 5. Function

x [a ] :

n x

x to the nth power x to the power of n

especially

x x

2

: x squared, x square, x to the second power : x cubed, x cube, x to the third power

3

1

n

x[x n] :

the nth root of x, x to the power of one over n

x : the

3

especially:

square root of x

x :

the cube root of x

Logax: the logarithm of x with the base a especially: lgx[log10x] the common [ordinary] logarithm of x

ln x

[ log

e

x]

: the natural logarithm of x

sin cos

?

2

the sine of Pi over two. the cosine of Pi over two the tangent of alpha the cotangent of alpha

?

2

tan ? [ tg ? ]

cot ? [ ctg ? ]

sec ?

cos ec ?

the secant of alpha the cosecant of alpha the differential of f with respect to x

5

df(x)

dt dx

d

2

[ f ' ( x )]

f

2

the first derivative of f with respect to x the second derivative of f with respect to x

[ f ' ' ( x )]

dx

?f ?x

? f

2

the first partial derivative of f with respect to x

2

?x

2

the second partial derivative of f with respect to x the second mixed partial derivative with respect to x and y. the (complete) differential of f with respect to x and y. the indefinite integral of f with respect to x the definite integral of f with respect to x from a to b (over the

? f ?x?y

df ( xy )

?

f ( x ) dx

b

?

( x) dx

a

interval from a to b)

? c ? a f ( x . y ) dxdy

d b

the double integral of f with respect to x from a to b and

with respect to y from c to d ▽f: gradient of f. ▽·A: divergence of A ▽A: curl of A. ▽2f [△f]: Laplacian f. 参考书目： 《数、符号、公式、图形的英文表达》 ，东南大学出版社 《英汉科学技术词典》 ，国防工业出版社

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