Câu hỏi của Khải Minh Bùi

Question

undefined em cần gấp ạ.Giúp em với!!!!!!!!!!!!!!!!!!!!!!

Nguyễn Việt Lâm · Accepted Answer

$A=\dfrac{1}{101}+\dfrac{1}{102}+...+\dfrac{1}{200}$

$A< \dfrac{1}{100}+\dfrac{1}{100}+...+\dfrac{1}{100}=100.\dfrac{1}{100}=1$

$\Rightarrow A< 1$

$A>\dfrac{1}{200}+\dfrac{1}{200}+...+\dfrac{1}{200}=100.\dfrac{1}{200}=\dfrac{1}{2}$

$\Rightarrow A>\dfrac{1}{2}$

$\Rightarrow\dfrac{1}{2}< A< 1$

Câu trả lời:

$A=\dfrac{1}{101}+\dfrac{1}{102}+...+\dfrac{1}{200}$

$A< \dfrac{1}{100}+\dfrac{1}{100}+...+\dfrac{1}{100}=100.\dfrac{1}{100}=1$

$\Rightarrow A< 1$

$A>\dfrac{1}{200}+\dfrac{1}{200}+...+\dfrac{1}{200}=100.\dfrac{1}{200}=\dfrac{1}{2}$

$\Rightarrow A>\dfrac{1}{2}$

$\Rightarrow\dfrac{1}{2}< A< 1$