数学公式的英语读法

17.2.1999/H. Va¨liaho Pronunciation of mathematical expressions The pronunciations of the most common mathematical expressions are given in the list below. In general, the shortest versions are preferred (unless greater precision is necessary). 1. Logic ∃ there exists ∀ for all p⇒ q p implies q / if p, then q p⇔ q p if and only if q /p is equivalent to q / p and q are equivalent 2. Sets x ∈ A x belongs to A / x is an element (or a member) of A x /∈ A x does not belong to A / x is not an element (or a member) of A A ⊂ B A is contained in B / A is a subset of B A ⊃ B A contains B / B is a subset of A A ∩B A cap B / A meet B / A intersection B A ∪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 3. Real numbers x+ 1 x plus one x− 1 x minus one x± 1 x plus or minus one xy xy / x multiplied by y (x− y)(x+ y) x minus y, x plus y x y x over y = the equals sign x = 5 x equals 5 / x is equal to 5 x 6= 5 x (is) not equal to 5 1 x ≡ y x is equivalent to (or identical with) y x 6≡ y x is not equivalent to (or identical with) y x > y x is greater than y x ≥ y x is greater than or equal to y x < y x is 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 0 ≤ x ≤ 1 zero is less than or equal to x is less than or equal to 1 |x| mod x / modulus x x2 x squared / x (raised) to the power 2 x3 x cubed x4 x to the fourth / x to the power four xn x to the nth / x to the power n x−n x to the (power) minus n √ x (square) root x / the square root of x 3 √ x cube root (of) x 4 √ x fourth root (of) x n √ x nth root (of) x (x+ y)2 x plus y all squared(x y )2 x over y all squared n! n factorial xˆ x hat x¯ x bar x˜ x tilde xi xi / x subscript i / x suffix i / x sub i n∑ i=1 ai the sum from i equals one to n ai / the sum as i runs from 1 to n of the ai 4. Linear algebra ‖x‖ the norm (or modulus) of x −−→ OA OA / vector OA OA OA / the length of the segment OA AT A transpose / the transpose of A A−1 A inverse / the inverse of A 2 5. Functions f(x) fx / f of x / the function f of x f : S → T a function f from S to T x 7→ y x maps to y / x is sent (or mapped) to y f ′(x) f prime x / f dash x / the (first) derivative of f with respect to x f ′′(x) f double–prime x / f double–dash x / the second derivative of f with respect to x f ′′′(x) f triple–prime x / f triple–dash x / the third derivative of f with respect to x f (4)(x) f four x / the fourth derivative of f with respect to x ∂f ∂x1 the partial (derivative) of f with respect to x1 ∂2f ∂x21 the second partial (derivative) of f with respect to x1∫ ∞ 0 the integral from zero to infinity lim x→0 the limit as x approaches zero lim x→+0 the limit as x approaches zero from above lim x→−0 the limit as x approaches zero from below loge y log y to the base e / log to the base e of y / natural log (of) y ln y log y to the base e / log to the base e of y / natural log (of) y Individual mathematicians often have their own way of pronouncing mathematical expres- sions and in many cases there is no generally accepted “correct” pronunciation. Distinctions made in writing are often not made explicit in speech; thus the sounds fx may be interpreted as any of: fx, f(x), fx, FX, FX, −−→ FX . The difference is usually made clear by the context; it is only when confusion may occur, or where he/she wishes to emphasise the point, that the mathematician will use the longer forms: f multiplied by x, the function f of x, f subscript x, line FX, the length of the segment FX, vector FX. Similarly, a mathematician is unlikely to make any distinction in speech (except sometimes a difference in intonation or length of pauses) between pairs such as the following: x+ (y + z) and (x+ y) + z √ ax+ b and √ ax+ b an − 1 and an−1 The primary reference has been David Hall with Tim Bowyer, Nucleus, English for Science and Technology, Mathematics, Longman 1980. Glen Anderson and Matti Vuorinen have given good comments and supplements. 3