csat-suneung 2014 Q6

csat-suneung · South-Korea · csat__math-A 3 marks Arithmetic Sequences and Series Find Common Difference from Given Conditions

For an arithmetic sequence $\left\{ a _ { n } \right\}$ with first term 6 and common difference $d$, let $S _ { n }$ denote the sum of the first $n$ terms. When
$$\frac { a _ { 8 } - a _ { 6 } } { S _ { 8 } - S _ { 6 } } = 2$$
holds, what is the value of $d$? [3 points]
(1) $-1$
(2) $-2$
(3) $-3$
(4) $-4$
(5) $-5$

For an arithmetic sequence $\left\{ a _ { n } \right\}$ with first term 6 and common difference $d$, let $S _ { n }$ denote the sum of the first $n$ terms. When

$$\frac { a _ { 8 } - a _ { 6 } } { S _ { 8 } - S _ { 6 } } = 2$$

holds, what is the value of $d$? [3 points]\\
(1) $-1$\\
(2) $-2$\\
(3) $-3$\\
(4) $-4$\\
(5) $-5$

Paper Questions

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