Question

Вычислите: 2/1×3+2/3×5+...+2/205×207
(Подробно)​

Answer 1

$\frac{2}{1*3}+\frac{2}{3*5}+...+\frac{2}{205*207}=\frac{1}{1}-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+...+\frac{1}{205}-\frac{1}{207}=1-\frac{1}{207}=\frac{206}{207}\\\\Otvet:\boxed{\frac{206}{207}}$