D= 1/3.5 + 1/5.7 + 1/7.9 + .. + 1/97.99 01/12/2021 Bởi Parker D= 1/3.5 + 1/5.7 + 1/7.9 + .. + 1/97.99
`D= 1/(3.5) + 1/(5.7) +1/(7.9)+…+ 1/(97+99)` `D= 1/2. ( 2/(3.5) + 2/(5.7) +…+ 2/(97.99))` `D= 1/2 . ( 1/3 – 1/5 + 1/5 -1/7 +…+ 1/97 – 1/99)` `D= 1/2 . (1/3 – 1/99)` `D= 1/2 . (33/99 – 1/99)` `D= 1/2 . 32/99` `D=16/99` ~ Học tốt ~ #TEAM_IQ_2000 Bình luận
Đáp án: \(S=\dfrac{1}{3.5}+\dfrac{1}{5.7}+\dfrac{1}{7.9}+…+\dfrac{1}{97.99}\) \(2S=\dfrac{2}{3.5}+\dfrac{2}{5.7}+\dfrac{2}{7.9}+…+\dfrac{2}{97.99}\) \(2S=\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{9}+…+\dfrac{1}{97}-\dfrac{1}{99}\) \(2S=\dfrac{1}{3}-\dfrac{1}{99}\) \(2S=\dfrac{32}{99}\) \(S=\dfrac{32}{99}:2\) \(S=\dfrac{16}{99}\) Giải thích các bước giải: Bình luận
`D= 1/(3.5) + 1/(5.7) +1/(7.9)+…+ 1/(97+99)`
`D= 1/2. ( 2/(3.5) + 2/(5.7) +…+ 2/(97.99))`
`D= 1/2 . ( 1/3 – 1/5 + 1/5 -1/7 +…+ 1/97 – 1/99)`
`D= 1/2 . (1/3 – 1/99)`
`D= 1/2 . (33/99 – 1/99)`
`D= 1/2 . 32/99`
`D=16/99`
~ Học tốt ~
#TEAM_IQ_2000
Đáp án:
\(S=\dfrac{1}{3.5}+\dfrac{1}{5.7}+\dfrac{1}{7.9}+…+\dfrac{1}{97.99}\)
\(2S=\dfrac{2}{3.5}+\dfrac{2}{5.7}+\dfrac{2}{7.9}+…+\dfrac{2}{97.99}\)
\(2S=\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{5}-\dfrac{1}{7}+\dfrac{1}{7}-\dfrac{1}{9}+…+\dfrac{1}{97}-\dfrac{1}{99}\)
\(2S=\dfrac{1}{3}-\dfrac{1}{99}\)
\(2S=\dfrac{32}{99}\)
\(S=\dfrac{32}{99}:2\)
\(S=\dfrac{16}{99}\)
Giải thích các bước giải: