解析 【解析】arithmetic sequence是等差数列的意思如果是等差数列那么I和II肯定符合啊I:an=a1+(n-1)d那么2an=2a1+(n-1)*2*d,则首项为2a1,公差为2d的等差数列II:an=a1+(n-1)dan-3=a1-3+(n-1)d,则首项为a1-3,公差为d的等差数列你举的例子不符合等差数列。。
2015amc8 18***An arithmetic sequence is a sequence in which each term after the first is obtained by adding a constant to the previous term. Each row and each column in this 5×5 array is an arithmetic sequence with five terms. What is the value of X? A.21 B.31 C.36 D.40 E....
Substituting n =100, d=1/2 S_n=145 nto the above formula, we get: 145=100a_1+(100*99)/2*1/2 Solving for a1 , a_1=-23.3 . a1,a3, a5,, ag9 is an arithmetic sequence with 50 terms, the common difference of 2d =2 × =1, and the first term of-23. 3. Therefore a_1...
(b) gives 10a+50d=170(a)is 10a+45d=162Subtract 5d=8 so d=1.6 o.e.Solving for a a=17-5d so a=9(a) M1 for use of S, with n =10(b) 1st M1 for an attempt to eliminate a or d fro m their two linear equations2nd M1 for using their value of a or d to find the ...
A series is the sum of the terms in a sequence, so an arithmetic series is the sum of the terms in an arithmetic sequence. Let S represent the sum: S=a_1+a_2+a_3++a_(n-2)+a_(n-1)+a_n. Write the sum again, except write the terms from last term to first term: S=a_...
百度试题 结果1 题目The sequence , , , , is an arithmetic progression. What is ?( ) A: B: C: D: E: 相关知识点: 试题来源: 解析 B N/A. 反馈 收藏
百度试题 结果1 题目【题目】In an arithmetic sequence, what is the relationship between the second term + eighth term and the fourthterm+sinthterm? 相关知识点: 试题来源: 解析 【解析】a_2+a_8=a_4+a_6 反馈 收藏
The sequence 2, 4, 6, 8,... is an arithmetic sequence. What is the common difference? A. 1 B. 2 C. 3 D. 4 相关知识点: 试题来源: 解析 B。解析:这个数列是等差数列,后一项减去前一项为定值,4-2=2,6-4=2,8-6=2,所以公差是 2。
, so the sum of the first n terms of the arithmetic series, S, is equal to one-half the number of terms multiplied by the sum of the first and last terms. That is, . Find the sum of the terms in the sequence 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. ...
6, and the seventh term is 24, then the common difference of the arithmetic sequence is , and the sum of all the 15 terms is . 相关知识点: 试题来源: 解析 3;405 (24–6)÷(7−1)=3. Then the 8th term is 24+3=27. The sum of all the terms is 27×15=405....