$\frac{1}{13}$ + $\frac{3}{13.23}$ + $\frac{3}{23.33}$ +…+ $\frac{3}{2303.2306}$ 30/07/2021 Bởi Reagan $\frac{1}{13}$ + $\frac{3}{13.23}$ + $\frac{3}{23.33}$ +…+ $\frac{3}{2303.2306}$
bạn tham khảo nha Ta có: 7/3.13 + 7/13.23 + 7/23.33 + 7/33.43 =7.10/3.13.10 + 7.10/13.23.10 + 7.10/23.33 + 7.10/33.43 = 7/10.(1/3-1/13+1/13-1/23+1/23-1/33+1/33-1/43) = 7/10.(1/3-1/43) = 7/10 . 14/43 = 49/215 học tốt Bình luận
bạn tham khảo nha
Ta có: 7/3.13 + 7/13.23 + 7/23.33 + 7/33.43
=7.10/3.13.10 + 7.10/13.23.10 + 7.10/23.33 + 7.10/33.43
= 7/10.(1/3-1/13+1/13-1/23+1/23-1/33+1/33-1/43)
= 7/10.(1/3-1/43) = 7/10 . 14/43
= 49/215
học tốt