B=\(\dfrac{1}{2!}\)+\(\dfrac{2}{3!}+\dfrac{3}{4!}\)+...+\(\dfrac{99}{100!}\)

=\(\dfrac{2-1}{2!}\)+\(\dfrac{3-1}{3!}+\dfrac{4-1}{4!}\)+...+\(\dfrac{100-1}{100!}\)

=\(\dfrac{2}{2!}-\dfrac{1}{2!}+\dfrac{3}{3!}-\dfrac{1}{3!}+\dfrac{4}{4!}-\dfrac{1}{4!}+...+\dfrac{100}{100!}-\dfrac{1}{100!}\)

=\(\dfrac{1}{1!}-\dfrac{1}{2!}+\dfrac{1}{2!}-\dfrac{1}{3!}+\dfrac{1}{3!}-\dfrac{1}{4!}+...+\dfrac{1}{99!}-\dfrac{1}{100!}\)

=\(1-\dfrac{1}{100!}\)< 1

\(\Rightarrow\)B =\(\dfrac{1}{2!}\)+\(\dfrac{2}{3!}+\dfrac{3}{4!}\)+...+\(\dfrac{99}{100!}\) < 1

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My favorite programme is "A Walk To Remember". This is my favorite movie because it deals with real life issues, like some of the most important things in life such as: love, relationships, and most important, who your real friends are. "A Walk To Remember is about a girl named Jamie (Mandy Moore) who is the daughter of a minister who becomes ill. During high school Jamie doesn't have very many friends but is in alot of activities and through that she meets a reckless boy named Landon. Landon got into some trouble which made the principal force him into being in a play for the drama club. Landon Played a lead role as did Jamie, even though they didn't hang out in the same crowd of friends when Landon needed Giúp with his lines in the play he turned to Jamie to Giúp him out. One of the first things she told Landon was for him to promise that he wouldn't fall in love with her. But that is a promise that he did not keep. Jamie finally told Landon that she had cancer and the treatment stoped working so she didn't have very much time to live. Jamie had this list of accomplisments that she wanted to make before she passed. The number one thing was to get married at the same church that her mother and father was married in. Landon made ALL of her dreams come true. But unfortunitally her cancer became worse and she died. I would recommend this movie to anyone who likes heart touching stories, I liked it and would watch it a million times a day if I could.

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My favorite movie is "A Walk To Remember". This is my favorite movie because it deals with real life issues, like some of the most important things in life such as: love, relationships, and most important, who your real friends are. "A Walk To Remember is about a girl named Jamie (Mandy Moore) who is the daughter of a minister who becomes ill. During high school Jamie doesn't have very many friends but is in alot of activities and through that she meets a reckless boy named Landon. Landon got into some trouble which made the principal force him into being in a play for the drama club. Landon Played a lead role as did Jamie, even though they didn't hang out in the same crowd of friends when Landon needed Giúp with his lines in the play he turned to Jamie to Giúp him out. One of the first things she told Landon was for him to promise that he wouldn't fall in love with her. But that is a promise that he did not keep. Jamie finally told Landon that she had cancer and the treatment stoped working so she didn't have very much time to live. Jamie had this list of accomplisments that she wanted to make before she passed. The number one thing was to get married at the same church that her mother and father was married in. Landon made ALL of her dreams come true. But unfortunitally her cancer became worse and she died. I would recommend this movie to anyone who likes heart touching stories, I liked it and would watch it a million times a day if I could.

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Vì rượu giãn nở vì nhiệt nhiều hơn thủy tinh

\(\dfrac{2}{7}\)

Gọi \(\dfrac{1}{3}\)+\(\dfrac{1}{3^2}\)+\(\dfrac{1}{3^3}\)+...+\(\dfrac{1}{3^8}\) là A

\(\Rightarrow\)A= \(\dfrac{1}{3}\)+\(\dfrac{1}{3^2}\)+\(\dfrac{1}{3^3}\)+...+\(\dfrac{1}{3^8}\)

\(\Rightarrow\)3A= 1+ \(\dfrac{1}{3}\)+\(\dfrac{1}{3^2}\)+\(\)...+\(\dfrac{1}{3^7}\)

\(\Rightarrow\)3A-A= (1+ \(\dfrac{1}{3}\)+\(\dfrac{1}{3^2}\)+\(\)...+\(\dfrac{1}{3^7}\)) - (\(\dfrac{1}{3}\)+\(\dfrac{1}{3^2}\) +\(\dfrac{1}{3^3}\)+...+\(\dfrac{1}{3^8}\) )

\(\Rightarrow\)2A= 1+ \(\dfrac{1}{3}\)+\(\dfrac{1}{3^2}\)+\(\)...+\(\dfrac{1}{3^7}\) - \(\dfrac{1}{3}\)-\(\dfrac{1}{3^2}\)-\(\dfrac{1}{3^3}\)-...-\(\dfrac{1}{3^8}\)

= 1-\(\dfrac{1}{3^8}\)

= \(\dfrac{6550}{6561}\)

\(\Rightarrow\)A= \(\dfrac{6550}{6561}\):2= \(\dfrac{6550}{6561}\).\(\dfrac{1}{2}\)=\(\dfrac{3280}{6561}\)

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The comparison between the rural and urban lifestyle has always been the most controversial topic of the modern days. Living in the countryside gives us fresher air, and a more quiet environment, which is good for people's healths, particularly to those who has suffered so much from the city's polution and crowdedness. People can also have a larger area to build up vegetable or flower gardens, to dig a fish pond, etc. Meanwhile, it's more difficult to find a variety of jobs in the countryside, and other such services as internet, electricity, healthcare, education… are also of lower qualities. However, as urbanization is happenning everywhere, this will no longer be so big a problem in the near future. Besides, as the transportation infrastructure is being improved, more and more people are choosing to live in the suburb and commute to the city center. The environment in which we live has a lot of influences on how lifestyle. However, it's up to ourselves to take the most advantages and get around the limitations.

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Last summer, I went to Nha Trang beach and Vung tau beach. But I like Nha Trang beach than Vung Tau beach. After the exam, I were gone to sea by my family. Nha trang is a wonderful beach. I were go to Nha Trang by train. Oh my god. What a awful trip! I take off the train at haft past two, I take on the train station at haft past eleven. But I happy with days at Nha Trang. Next day, I get up at six o'clock. I went to restaurant for breakfast and drinking coffee in order to not tired when going to play. Next, I went to harbor so as to go to the island. Then the ship go to the island, All people in the ship are shock expect my father, friend of my father, touristman. In Distance, I take the sea. The water of the sea is fresh, cool. In the bottom of the sea, we can see the coral. It's beautiful. Next, I went to other islands for visit and come back the harbor before come back the hotel. In the hotel, I rest thirty minutes before eat the dinner. In the evening, I take the motorbike ride along the beach in order to go for a sightseeing Nha Trang City.
What a wonderful trip! I happy after the trip. The trip will help me study well.

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It can be said, social network is gradually occupy important position, affecting not only small human life, especially the young. But it also needs to know how to use social networks scientifically so that it becomes a useful tool in life rather than being turned into its "slave". From then on, leverage and promote the positive benefits that social networking bring, limit and eliminate the negative impact caused by the number of users. Facebook is a great example, let's say it's a place to share useful information, information and sympathy, and be cautious with open relationships that you can easily get with just one click. mouse. I can not imagine how they would bring about "disastrous" surprises ...
A recent study at an American university shows:

Students using FB have less than 20% study results compared to other students.

Outside the classroom, 88% of non-FB students actively participate in extracurricular activities.75% of students using FB do not think that this social network will reduce learning outcomes.
Some of the biggest negative effects that social networks have on children today are:

High self-esteem.

Psychological disorders, including anti-social behavior, paranoia, negative life, excessive drinking.

Frequent dropouts, high risk of stomach pain, insomnia, anxiety, depression.

Poor academic results.

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