Gaokao Math Practice Question
设 $\triangle A_{n} B_{n} C_{n}$ 的三边长分别为 $a_{n}, b_{n}, c_{n}, \triangle A_{n} B_{n} C_{n}$ 的面积为 $S_{n}, n=1, 2 , 3...$ 若 $b_{1}>c_{1}, \quad b_{1}+c_{1}=2 a_{1}, \quad a_{n+1}=a_{n}, \quad b_{n+1}=\frac{c_{n}+a_{n}}{2}, \quad c_{n+1}=\frac{b_{n}+a_{n}}{2}$, 则 （$\qquad$）
- A.$\left\{S_{n}\right\}$ 为递减数列
- B.$\left\{S_{n}\right\}$ 为递增数列
- C.$\left\{S_{2 n-1}\right\}$ 为递增数列, $\left\{S_{2 n}\right\}$ 为递减数列
- D.$\left\{S_{2 n-1}\right\}$ 为递减数列, $\left\{S_{2 n}\right\}$ 为递增数列
Want to know if you got it right?
Answer this and thousands more real Gaokao previous-year questions free, get graded instantly, and climb the global ranked leaderboard.
Practice Gaokao free →More Gaokao Math questions
- 设集合 A=\{x \mid x \geq 1\}, B=\{x \mid-1<x<2\}, 则 A \cap B= (\quad)…
- 已知 a \in R,(1+a i) i=3+i, ( i 为虚数单位), 则 a=(\quad)…
- 已知非零向量 \vec{a}, \vec{b}, \vec{c}, 则“ \vec{a} \cdot \vec{c}=\vec{b} \cdot \vec{c} ”是“ \vec{…
- 若实数 x, y 满足约束条件 \left\{\begin{array}{l}x+1 \geq 0 \\ x-y \leq 0 \\ 2 x+3 y-1 \leq0\end{arr…
- 已知 a, b \in \mathrm{R}, a b>0, 函数 f(x)=a x^{2}+b(x \in \mathrm{R}). 若 f(s-t), f(s), f(s+t)…
- 已知数列 \left\{a_{n}\right\} 满足 a_{1}=1, a_{n+1}=\frac{a_{n}}{1+\sqrt{a_{n}}}\left(n \in \mat…
- 设 z=\frac{1-i}{1+i}+2 i, 则 |z|=(\qquad)…
- 已知集合 A=\left\{x \mid x^{2}-x-2>0\right\}, 则 C_{R} A=（ \qquad ）…