“微信扫一扫”进入题库练习及模拟考试
已知等差数列\(\left\{ {{a_n}} \right\}\)满足\({a_4} = {a_1} + {a_2}\),且\({a_1} \ne 0\),则\(\frac{{{a_5}}}{{{a_1} + {a_3}}} = \)___.
参考答案:1
解析:
因为\({a_4} = {a_1} + {a_2}\),所以\({a_1} + 3d = {a_1} + {a_1} + d\),即\({a_1} = 2d\).
因为\({a_1} \ne 0\),则\(d \ne 0\),
所以\(\frac{{{a_5}}}{{{a_1} + {a_3}}} = \frac{{{a_1} + 4d}}{{{a_1} + {a_1} + 2d}} = \frac{{6d}}{{6d}} = 1\).
故答案为:1
进入考试题库