수학1_무한급수_교대급수_난이도 중

무한급수 $\left ( \dfrac{3}{2} - \dfrac{4}{3} \right )+\left ( \dfrac{4}{3} - \dfrac{5}{4} \right )+\left ( \dfrac{5}{4} - \dfrac{6}{5} \right )+\cdots$ 의 합은?

① $\dfrac{1}{4}$          ② $\dfrac{1}{3}$          ③ $\dfrac{1}{2}$          ④ $1$          ⑤ $\dfrac{3}{2}$         

정답 ③