专业英语中的常用符号和数学式表达 (1)

专业英语中的常用符号和数学式的表达

1/2 a half, one half

1/3 a third, one third

2/3 two thirds

1/4 a quarter, one quarter, a fourth, one fourth

1/100 a(one) hundredth

1/1000 a(one) thousandth

113/324 one hundred and thirteen over three hundred and twenty four

2

four and two thirds

4

3

0.25zero (0, naught) point two five

+ plus , positive

_ minus, negative

±plus or minus

×multiplied by , times

÷divided by

= be equal to, equals

≈be approximately equal to, approximately equals

() round brackets; parentheses

【】square (angular) brackets

{} braces

≤less than or equal to

≥more than or equal to

∞infinity

∵because

∴therefore

maps into

X+y x plus y

(a+b) bracket a plus b bracket closed

A=b a equals b; a is equal to b; a is b

A≠b a is not equal to b

A±b a plus or minus b

A≈b a is approximately equal to b

A＞b a is greater than b

A＞＞b a is much[far] greater than b

A

A<

A⊥b a is perpendicular to b

X ∞x approaches infinity

A≡b a is identically equal to b; a is of identity to b ∠a angle a

A～b the difference between a and b

A∥b a is parallel to b

A∝b a varies directly as b

2

x: x square; x squared; the square of x; the second power of x; x to second power

3

x: x cube; x cubed; the cube of x; the third power of x; x to the third power

x the square root of x

3x the cube root of x

% percent

2% two percent

‰per mill

5‰five per mill

log

x log x to the base n

n

log x log x to the base 10; common logarithm 10

log

x, ln x log x to the base e; natural logarithm;

e

napierian logarithm

x

e,exp()x exponential function of x;e to the power x

n

x the nth power of x; x to the power n

1n

x或n x the nth root of x; x to the power one over n

Sin sine

Cos cosine

Tg, tan tangent

Ctg, cot cotangent

Sc, sec secont

Csc, coses cosecant

1sin - , arcsin : arc sine

1cos -, arcos : arc cosine

Sinh : the hyperbolic sine

Cosh: the hyperbolic cosine

∑: the summation of

1

n

i i x =∑: the summation of x sub I, where I goes from

1 to n

∏: the product of

x : the absolute value of x

x : the mean value of x; x bar

b ': b prime

b '': b double prime; b second prime

b ''': b triple prime

()f x : function f of x

∧ ； finite difference or increment

x ∆: the increment of x

dx : dee x; dee of x; differential x

dy

dx : the differential coefficient of y with respect to

x;

the first derivative of y with respect of x