专业英语中常用符号和数学表达式大全

专业英语中常用符号和数学表达式
1．数的分类
complex number 复数        zero; naught;0 零
real number 实数        imaginary number 虚数
relational number 有理数        irrational number 无理数
integer number 整数        positive integer number 正整数
natural number 自然数        negative integer number 负整数
fraction 分数        decimal 小数
odd number 奇数        even number 偶数
cardinal number 基数        ordinal number 序数
approximate number 近似数        significant number 有效数

2．整数
addition 加法        subtraction 减法
addend 加数        subtrahend 减数
augend 被加数        minuend 被减数
plus sign 加号        minus sign 减号
sum 和        difference（diffa）差
plus; add; and; increase 加        minus; decrease; subtract 减
is; equal 等        division 除法
multiplication 乘法        divide 除
multiply; multiplied by; times 乘        divisor 除数
multiplier 乘数        dividend 被除数
multiplicand 被乘数        quotient 商
product 积        remainder 余数
positive 正        negative 负

3．小数和分数
numerator 分子        denominator 分母
decimal point 小数点        naught point four 零点四
fraction stroke 分数线        recurring decimal 循环小数

4．百分数
percent 百分比        interest 利息
average 平均数        round off 舍入
discount 折扣       

5．幂与指数
power 幂; 乘方        root-extracting 开方
exponent 指数        logarithms 对数
X squared 某数的平方        cube 三次方
three cubed 三次方的        four 乘四次方
cube root 立方根        square root 平方根
to rise to the power of five 使乘五次方        radical sign根号

6．代数
algebra 代数        equation 等式; 方程式
inequality 不等式        unknown number 未知数
absolute value绝对值        simple equation 一次方程
quadratic equation 二次方程        cubic equation 三次方程
monomial 单项式        polynomial 多项式
variable 变量        coefficient 系数
differential 微分        integral 积分
derivative 导数        function 函数
ratio 比        proportion 比例
sign of equality等号        sign of inequality不等号
interval 区间        matrix 矩阵
theorem 定理        lemma 引理
definition 定义       

7．常用数学表达式
1/2
a half; one half
l/3        a third; one third
2/3        two thirds
1/4        a quarter; one quarter; a fourth; one fourth
l/100        a（one）hundredth
l/1,000        a（one）thousandth
113/324        one hundred and thirteen over three hundred and twenty-four

four and two-thirds

forty-five and eighty-nine over twenty-three
0.1        one tenth; point one
0.01        one hundredth; point zero one
0.001        one thousandth; point zero zero one; point two zero one
2050.0357        two thousand and fifty point zero three five seven
0.25        zero point two five

point two five repetend five

zero point two five recurring

zero point three seven twenty-five recurring
对483579四舍五入到千位        round off 483579 to nearest thousand
108        one followed by eighteen zeros
-30.8        negative thirty point eight
2-3i        two minus three i; two minus three times i
2％        two per cent; two percent
5‰        five per mill; five permill
∞        infinity
x＋y＝z
x plus y is z; add x to y is z; x and y is z
(x＋y)        bracket x plus y bracket closed
x-y        x minus y; subtract y from x; y from x; x subtracts y
x±y        x plus or minus y
x×y; xy        xy; multiply x by y; x multiplied by y; x by y; x times y;
x÷y
divide x by y; y into x
        x over y
x : y        the ration of x to y
x∝y        x varies as y; x is in direct proportion to y
x＝y        x equals y; x is equal to y; x is y
x≠y        x is not equal to y; x is not y
x≡y        x is identical to y; x is equivalent to y; x is equivalent to y;
x≈y        x is approximately equal to y; x approximately equals y
x＞y        x is greater than y; x is more than y
x>>y        x is much greater than y; x is far greater than y
x≥y        x is greater than or equal to y
x＜y        x is less than y
x<<y        x is much less than y
x≤y        x is less than or equal to y
0＜x＜1        zero is less than x is less than 1; x is greater than zero and less than 1
0≤x≤1        zero is less than or equal to x is less than or equal to 1
x2        x square; x squared; the square of x;
the second power of x; x to second power
x3        x cube; x cubed; the cube of x;
the third power of x; x to the third power
xn        the nth power of x; x to the nth power; x to the power n

the square root of x; x squared

the cube root of x

the nth root of x
x-n        x to the (power) minus n
(x+y)2
x plus y all squared
        x over y all squared
x i        x i; x subscript i; x suffix i; x sub i
lognx
log x to the base n; log of x to the base n
log10x        log x to base 10; common logarithm
logex; lnx        log x to the base e; log to the base e of y; natural log (of) y
ex; exp(x)        exponential function of x, e to the power x

the summation of x sub i, where i goes from 1 to n;
the sum from i equals one to n x i;
the sum as i runs from one to n of the x i

the product of x sub i, where i goes from one to n
the product of all x i from i equals one to n
        the product of all xi from i equals one to infinity

the absolute value of x; mod x; modulus x

the mean value of x; x bar

x hat

x tilde
x*        x asterisk

x prime

x double prime

x double prime sub m
f(x)        f x; f of x; the function f of x

a function f from S to T
f&cent;(x)        f prime x; f dash x; the (1st) derivative of f with respect to x
f&sup2;(x)        f double–prime x; f double–dash x; the second derivative of f with respect to x
f&cent;&sup2;(x)        f triple–prime x; f triple–dash x; the third derivative of f with respect to x
f4(x)        four x; the fourth derivative of f with respect to x
x!        n factorial
△        finite difference or increment
△x,δx        the increment of x
dx        dee x; dee of x; differential x

del; nabla

nth del (nabla)

the differential coefficient of y with respect to x;
the first derivative of y with respect of x

the second derivative of y with respect of x

the nth derivative of y with respect of x
        the partial (derivative) of y with respect to u

the second partial (derivative) of y with respect to x

the partial derivation of z with respect to x of the partial derivative of z with respect to y
∫        integral of
∫∫        double Integral of
∫…∫        n-fold integral of

the integral between limits a and b; the integral from a to b

the indefinite integral of a times x with respect to x

the integral from a to b of function of x

the double integral of f of x,y

the limit as x approaches 0

the limit as x approaches 0 from above
       

the limit as x approaches 0 from below

there exists

for all
∵        because
∴        therefore
x⊥y        x is perpendicular to y
x∥y        x is parallel to y
x～y        the difference between x and y
x∝y        x varies directly as y
x&THORN;y        x implies y; if x, then y
x&Ucirc;y        x if and only if y; x is equivalent to y; x and y are equivalent
{ };  
empty set
x&Icirc;A        x belongs to A; x is an element (or a member) of A
x&Iuml;A        x does not belong to A; x is not an element (or a member) of A
A&Igrave;B        A is contained in B; A is a subset of B
A&Eacute;B        A contains B;B is a subset of A
A&Ccedil;B        A cap B; A meet B; A intersection B
A&Egrave;B        A cup B; A join B; A union B
A\B        A minus B; the difference between A and B
A×B        A cross B; the Cartesian product of A and B(A与B的笛卡尔积)
||A||
the norm (or modulus) of A

vector F

AB; the length of the segment AB
AT        A transpose; the transpose of A
A-1        A inverse; the inverse of A
x→y        x maps into y; x is sent (or mapped) to y
x→∞        x approaches infinity
∠x
angle x

x is perpendicular to y

x is parallel to y
sin        sine
cos        cosine
tg, tan        tangent
ctg, cot        cotangent
sc, sec        secant
csc, cosec        cosecant
sin-1, arcsin        arc sine
cos-1, arcos        arc cosine
sinh        the hyperbolic sine
cosh        the hyperbolic cosine
( )        round brackets; parentheses ;the signs of grouping
[ ]        square（angular）brackets; bracket
< >        angle bracket
{}        braces

8．常用希腊字母
字母        读音        字母        读音        字母        读音

alpha         
beta         ,
gama

xi         ,
psi         
delta

epsilon         
zeta         ,
phi

omega         
lambda         
mn

nu         
eta         
rho
,
sigma         
tau         
pi

9．其他数学名词
line 线        angle 角
intersecting line 相交线        parallel line 平行线
triangle 三角形        quadrilateral 四边形
rectangle 矩形        lozenge 菱形
square正方形        polygon多边形
circle圆        arc弧
perimeter周长        area面积
diameter直径        volume体积

10．具体读法实例
y=f(x)        y is a function of x
6×5＝30        six times (multiplied by) five equals (is equal to) thirty
(x-y)(x+y)        x minus y; x plus y

the fifth root of x square
y-10        y to the minus tenth (power)
20 : 5＝16 : 4        the ratio of 20 to 5 equals the ration of 16 to 4 (20 is to 5 as 16 is to 4)
e=1.6×10-19        e equals one point multiplied by ten to minus nineteenth power
10-n        ten to the minus n

one over n square

one over one minus n times z reverse
f(x)=ax2+bx+c        the function of x equals a times the square of x plus b times x plus c
|a|=b        the absolute value of a equals that of b
max f(x)        the maximum value of f(x)
min f(x)        the minimum value of f(x)
an&#61664;∞        a sub n approaches / tends to infinity

the limit of Sn as n gets arbitrarily large is one third

x to the fifth power plus A over (divided by) the quantity x squared plus B, to the two-thirds power
(A+B)C        the quantity A plus B times C
A+B=C        A plus B equals C
A-B=C        A minus B equals C
A×B=C        A multiplied by B equals C
A/B=C        A divided by B equals C
A : B=C : D        A is to B of A to B as C is to D

11．数学问题求解的一般表示
Solve the following system of equations


Solution: multiply equation (1) by (2) and get

Subtract equation (2) from equation (4), and get

Subtract equation (3) from equation (2), and get

from equation (5) from equation (6),obtain x and y.

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