If the first term of an arithmetic sequence is 5 and the common difference is 3, then the third term is ___. A. 11 B. 10 C. 12 D. 9 相关知识点: 试题来源: 解析 A。中文解析:首项\(a_1 = 5\),公差\(d = 3\),根据通项公式\(a_n = a_1 + (n - 1)d\),第三项\(a_...
In an arithmetic sequence, the sum of the first 15 terms is 450 and the sum of the first 20 terms is 750. Find the common difference and the first term in this sequence.. 相关知识点: 试题来源: 解析 3, 9.. The 8th term is 450÷15=30, and the 18th term is (750–450)÷(20...
The first term of an arithmetic sequence is −2468 while its last term is 2464 . If the common difference is 4 , find the sum of all its terms. 相关知识点: 试题来源: 解析 −2468. 2464−(−2468)4+1 =1233+1 =1234, [2464+(−2468)]×12342 =−4×617 =−2468. 故它的...
in that order. What is the fifth term?( ) A.−158 B.−65 C.0 D.2720 E.12340相关知识点: 试题来源: 解析 E The difference between consecutive terms is (x−y)−(x+y)=−2y. Therefore we can also express the third and fourth terms as x−3y and x−5y. Then we can ...
The sum of the first 10terms of the sequence is 162.(a) Show that 10a+45 d =162Given also that the sixth term of the sequence is 17.(b) write down a secon d equation in a an d d,(c) fin d the value of a an d the value of d. ...
北步元出她花日育结大它说节In an arithmetic sequence, the first term is 北步元出她花日育结大它说节北步元出她花日育结大它说节北
The sum of the first 5 terms of an arithmetic sequence is 45. If the first term is 3, what is the common difference? A. 2 B. 3 C. 4 D. 5 相关知识点: 试题来源: 解析 C。解析:等差数列前 n 项和公式为 Sn = n(a1 + an) / 2 ,因为是前 5 项,所以 n = 5 ,a1 = 3 ,Sn...
An arithmetic sequence has first term a and common difference d. The sum of the first 12 terms of the sequence is 366. Show that 12a+66d=366. Given also that the eighth term of the sequence is 38, 相关知识点: 试题来源: 解析 S_(12)= (12)2(2a+(12-1)d)=366 So 6(2a+11d...
, then the common difference of the arithmetic sequence is , and the sum of all the 13 terms is . 相关知识点: 试题来源: 解析 3;312 The common difference refers to the difference between any two adjacent terms in an arithmetic sequence. Give the first term is 6, the fifth term is 18...
The sum of the first five terms of an arithmetic sequence is 50. If the first term is 5, what is the common difference? A. 3 B. 4 C. 5 D. 6 相关知识点: 试题来源: 解析 B。解析:设公差为 d,根据等差数列求和公式,S5=5a1+(5×4/2)d=50,a1=5 代入可得 25+10d=50,解得 d=25...