\(A=1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+...+\dfrac{1}{49}-\dfrac{1}{50}\)

\(A=1-\dfrac{1}{50}\)

\(A=\dfrac{49}{50}\)

\(\dfrac{3}{3.5}+\dfrac{3}{5.7}+...+\dfrac{3}{47.49}+\dfrac{3}{49.51}\)

\(=\dfrac{3}{2}.(\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+...+\dfrac{1}{49}-\dfrac{1}{51})\)

\(=\dfrac{3}{2}.(\dfrac{1}{3}-\dfrac{1}{51})\)

\(=\dfrac{3}{2}.\dfrac{16}{51}\)

\(=\dfrac{8}{17}\)

5 câu với will/won't

- I will/ won't have a big and beautiful house

-I will/won't buy clother with my family

-I will/won't have a computer but it's very expensive

-It will/won't hot in the tomorrow

-I will/won't see rainbow butterfly in the garden

Em sẽ tỏ thái độ, báo cho cha mẹ, người thân và thầy cô giáo biết để được giúp đỡ

Em cảm ơn ạ