gaokao 2019 Q9

gaokao · China · national-I-science_gkztc Arithmetic Sequences and Series Find General Term Formula

9. Let $S _ { n }$ denote the sum of the first $n$ terms of an arithmetic sequence $\left\{ a _ { n } \right\}$ . Given $S _ { 4 } = 0 , a _ { 5 } = 5$ , then
A. $a _ { n } = 2 n - 5$
B. $a _ { n } = 3 n - 10$
C. $S _ { n } = 2 n ^ { 2 } - 8 n$
D. $S _ { n } = \frac { 1 } { 2 } n ^ { 2 } - 2 n$

Let $S _ { n }$ denote the sum of the first $n$ terms of an arithmetic sequence $\left\{ a _ { n } \right\}$. Given $S _ { 4 } = 0$,

9. Let $S _ { n }$ denote the sum of the first $n$ terms of an arithmetic sequence $\left\{ a _ { n } \right\}$ . Given $S _ { 4 } = 0 , a _ { 5 } = 5$ , then\\
A. $a _ { n } = 2 n - 5$\\
B. $a _ { n } = 3 n - 10$\\
C. $S _ { n } = 2 n ^ { 2 } - 8 n$\\
D. $S _ { n } = \frac { 1 } { 2 } n ^ { 2 } - 2 n$

Paper Questions

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