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Question

A = 1/1 mũ 2 + 1/2 mũ 2 + ... + 1/50 mũ 2

lê trọng đại(Hội Con 🐄)_(ツтєαм♕¢âи... · Accepted Answer

bai nay minh chua bao gio gapCâu trả lời: bai nay minh chua bao gio gap

Đức Lộc · Answer

$A=\frac{1}{1^2}+\frac{1}{2^2}+...+\frac{1}{50^2}$Có: $\hept{\begin{cases}\frac{1}{1^2}>\frac{1}{1\times2}\...\\frac{1}{50^2}>\frac{1}{50\times51}\end{cases}}$$\Rightarrow A>\frac{1}{1\times2}+\frac{1}{2\times3}+...+\frac{1}{50\times51}$$\Rightarrow A>1-\frac{1}{51}$$\Rightarrow A>\frac{50}{51}$Câu trả lời: $A=\frac{1}{1^2}+\frac{1}{2^2}+...+\frac{1}{50^2}$Có: $\hept{\begin{cases}\frac{1}{1^2}>\frac{1}{1\times2}\...\\frac{1}{50^2}>\frac{1}{50\times51}\end{cases}}$$\Rightarrow A>\frac{1}{1\times2}+\frac{1}{2\times3}+...+\frac{1}{50\times51}$$\Rightarrow A>1-\frac{1}{51}$$\Rightarrow A>\frac{50}{51}$

1. What’s your favourite drink?	a. No, thanks.	1.
2. What’s his favourite food?	b. My favourite drink is milk.	2.
3. Would you like some lemonade?	c. I go to school at six o’clock.	3.
4. What does your mother do?	d. Yes, please. I love noodles.	4.
5. Do you like orange juice?	e. She’s a clerk.	5.
6. What’s her favourite food?	f. His favourite food is chicken.	6.
7. Would you like some noodles?	g. His favourite drink is orange juice.	7.
8. Where does he work?	h. Yes, I do.	8.
9. What time do you go to school?	i. He works in a hospital.	9.
10. What’s his favourite drink ?	j. Her favourite food is beef.	10.

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