dhu佃户列(国外英语资料).docVIP

dhu佃户列(国外英语资料) Definition In general, if a series from second onwards, each with its first difference is equal to a constant, this series is called arithmetic sequence (arithmetic sequence), this is called constant arithmetic sequence (common, difference) tolerance tolerance usually D shown by the letter, before the N and Sn. Abbreviation The arithmetic progression can be abbreviated to A.P. (Arithmetic Progression). Arithmetic mean By three the number of a, A, B arithmetic sequence can be called the most simple arithmetic sequence. At this time, A called a and arithmetic mean B (arithmetic mean). Yes: A= (a+b) /2 General term formula An=a1+ (n-1) d an=Sn-S (n-1) (n = 2 an=kn+b (k), B constant) First n items and Reverse phase addition is before the N and formula: Sn=a1+a2+a3 --- +an =a1+ (a1+d) + (a1+2d) + --- +[a1+ (n-1) d] Sn=an+ (an-d) + (an-2d) + --- +[an- (n-1) d] 2 by 1 + 2 2Sn= (a1+an) + (a1+an) + (a1+an) (n) =n (a1+ an) Sn=n (a1+an) /2 solid sequence before the N and equal to two at the end of the first half of the number of items and product: Sn=n (a1+an) /2=n*a1+n (n-1) d/2 Sn= (d/2) *n^2+ (a1-d/2 n) Nature And any two am, an: an=am+ (n-m) for d it can be as general formula of generalized arithmetic progression. From the definition, the general formula of arithmetic progression, before the N and formula is also available: a1+an=a2+an-1=a3+an-2=... =ak+an-k+1, K, {1,2,... If m, n}, N, P, Q, N*, and m+n=p+q, a am+an=ap+aq S2n-1= (2n-1) an, S2n+1= (2n+1) an+1 Sk, S2k-Sk, S3k-S2k,... Snk-S (n-1) k... In an arithmetic progression, etc.. And (= first + at the end of 2, the number of items) * = (end - first), +1, =2 and tolerance first term - at the end of last term, and the number of =2 - the first set A1, A2, A3 sequence. A2 as the arithmetic mean of 2 times, while the A2 is equal to a1+a3, namely 2a2=a1+a3. application In daily life, people often use arithmetic sequence such as: in the size grade to the products, when the maximum size of the smallest size diff