GRE数学手册1

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

cube root of
∥  parallel to
⊥  perpendicular to, at right angles with
∠  angle
∟  right angle
?   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
lognx   log x to the base 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