gre数学考试在新gre考试当中增加了一些难度,但是gre考生也不要太紧张,只要把一些gre数学基本概念掌握好,解题时就一定能轻松应对。
, _ l/ G% L; w% L5 _ 排列组合) [# L# q/ \6 Q$ L5 j S4 ?
排列数公式和组合数公式:, f! w0 X' Q& w, G
乘法原理:) b6 {; Z* R& v# r( ~
一件事的完成可以分成n个步骤,完成其第一步有m1种方法,完成第二步有m2种方法……完成第n步有mn种方法,那么完成这件事一共有N=m1*m2*……*mn种不同的方法。 c, |0 V% i0 k) k3 v0 x) R0 j
例题.If all of the room numbers in a certain hotel must be even numbers, and if each of the numbers uses all four of the digits 3,4,5 and 8, what is the greatest number of four-digit numbers that the hotel can have?
" x! G7 o/ f" d. t 例题.What is the total number of different 4-digit integers in which the units’ digit is an odd integer while the thousands’ digit is an even integer?) A$ Q0 H) N1 K7 [. O) F
例题.What is the total number of different 5-digit numbers that contain all of the digits 1,2,3,4, and 5 and. l& x. H9 u9 O% ]5 x0 l
1) in which none of the odd digits occur next to each other?5 }/ c! N) l: d, c+ T
2) in which none of the even digits occur next to each other?
% `% s- U" w/ Z" J" j" h1 T 平时,gre考生一定要注意gre数学基本概念的加强理解,因为无论gre数学考试怎样的题目都是从最基本的概念中演变而来的。 |