新GRE數(shù)學重要考點平均數(shù)-智課教育旗下智課教育

1、 智 課 網(wǎng) G R E 備 考 資 料 新GRE數(shù)學重要考點平均數(shù)-智課教育旗下智課教育本文為廣大考生整理的新GRE數(shù)學重要考點之平均數(shù)，希望幫助大家解決GRE考試難題，預(yù)?？忌軌蛉〉煤玫某煽?。如果新GRE數(shù)學考點都沒有復習到，如何能拿到滿意的GRE數(shù)學分數(shù)呢?所以說，想要新GRE數(shù)學考好，復習的時候一定要把新GRE數(shù)學考點弄扎實。Average of n numbers of arithmetic progression (AP is theaverage of the smallest and the largest number of them. Theaverage of m nu

2、mber can also be written as x + d(m-1/2.Example:The average of all integers from 1 to 5 is (1+5/2=3The average of all odd numbers from 3 to 3135 is(3+3135/2=1569The average of all multiples of 7 from 14 to 126 is(14+126/2=70remember:Make sure no number is missing in the middle.With more numbers, ave

3、rage of an ascending AP increases.With more numbers, average of a descending AP decreases.AP:numbers from sumgiven the sum s of m numbers of an AP with constantincrement d, the numbers in the set can be calculated as follows:the first number x = s/m - d(m-1/2,and the n-th number iss/m + d(2n-m-1/2.E

4、xample:if the sum of 7 consecutive even numbers is 70, then the firstnumber x = 70/7 - 2(7-1/2 = 10 - 6 = 4.the last number (n=m=7is 70/7+2(27-7-1/2=10+6=16.theset is the even numbers from 4 to 16.Remember: given the first number x, it is easy to calculate other numbersusing the formula for n-th num

5、ber: x+(n-1AP:numbers from averageall m numbers of an AP can be calculated from the average.the first number x = c-d(m-1/2, and the n-th number isc+d(2n-m-1/2, where c is the average of m numbers.Example:if the average of 15 consecutive integers is 20, then the firstnumber x=20-1(15-1/2=20-7=13 and the last number (n=m=15is 20+1(215-15-1/2=20+7=27.if the average of 33 consecutive odd numbers is 67, then thefirst number x=67-2(33-1/2=67-32=35 and the last number(n=m=33 is 67+2(233-33-1/2=67+32=99.Remember:sum of the m numbers is cm,where c is the average.以上就是新GRE數(shù)學平均數(shù)考點的介紹?？忌灰^于緊張，把基本概念弄明白，