给文文的GRE数学手册【荐】.pdfVIP

主要符号 ＋ plus ;positive － minus ;negative × multiplied by ;times ÷ divided by ＝ equals ≈ approximately equals ≠ not equal to ＜ less than ＞ greater than ≤ equal to or less than ≥ equal to or greater than o ( ) round brackets ;parentheses [ ] square brackets { } braces ∈ is a member of the set ⊂ is a subset of ∽ similar to ≌ congruent to * denotes an operation ∴ therefore ∵ because ∶ ratio sign, divided by, is to ∷ equals, as(proportion) square root of 3 cube root of ∥ parallel to ⊥ perpendicular to, at right angles with ∠ angle ∟ right angle º degree ′ minute ″ second ⊙ circle A⁀B arc AB e the base of natural logarithms,approx.2.71828 x! factorial x, x(x-1)(x-2)1 log x log x to the base n n π pi lnx log x to the base e(natural logarithm) lgx log x to the base 10(common logarithm) |x| the absolute value of x 数的概念和特性 *几个 GRE 最常用的概念： 偶数(even number)：能被 2 整除的整数； 奇数(odd number)：不能被 2 整除的