S= 2/3+2/15+2/35+…+2/2303+2/2499 Tính tổng sau 11/08/2021 Bởi Brielle S= 2/3+2/15+2/35+…+2/2303+2/2499 Tính tổng sau
`S = 2/3 + 2/15 + 2/35 + … + 2/2303 + 2/2499` `⇒ S = 2/(1. 3) + 2/(3. 5) + 2/(5. 7) + … + 2/(47. 49) + 2/(49. 51)` `⇒ S = 1 – 1/3 + 1/3 – 1/5 + 1/5 – 1/7 + … + 1/47 – 1/49 + 1/49 – 1/51` `⇒ S = 1 – 1/51` `⇒ S = 51/51 – 1/51` `⇒ S = 50/51` Bình luận
`S = 2/3 + 2/15 + 2/35 + …. + 2/2033 + 2/2499` `S = 2/( 1 . 3 ) + 2/( 3 . 5 ) + 2/( 5 . 7 ) + …. + 2/( 47 . 49 ) + 2/( 49 . 51 )` `S = 1/1 – 1/3 + 1/3 – 1/5 + 1/5 – 1/7 + …. + 1/47 – 1/49 + 1/49 – 1/51` `S = 1 – 1/51` `S = 50/51` Bình luận
`S = 2/3 + 2/15 + 2/35 + … + 2/2303 + 2/2499`
`⇒ S = 2/(1. 3) + 2/(3. 5) + 2/(5. 7) + … + 2/(47. 49) + 2/(49. 51)`
`⇒ S = 1 – 1/3 + 1/3 – 1/5 + 1/5 – 1/7 + … + 1/47 – 1/49 + 1/49 – 1/51`
`⇒ S = 1 – 1/51`
`⇒ S = 51/51 – 1/51`
`⇒ S = 50/51`
`S = 2/3 + 2/15 + 2/35 + …. + 2/2033 + 2/2499`
`S = 2/( 1 . 3 ) + 2/( 3 . 5 ) + 2/( 5 . 7 ) + …. + 2/( 47 . 49 ) + 2/( 49 . 51 )`
`S = 1/1 – 1/3 + 1/3 – 1/5 + 1/5 – 1/7 + …. + 1/47 – 1/49 + 1/49 – 1/51`
`S = 1 – 1/51`
`S = 50/51`