\(\frac{1}{n\cdot\left(n+1\right)\cdot\left(n+2\right)\cdot\left(n+3\right)}\)= \(\frac{1}{3}\left(\frac{1}{n\cdot\left(n+1\right)\left(n+2\right)}-\frac{1}{\left(n+1\right)\cdot\left(n+2\right)\cdot\left(n+3\right)}\right)\)
\(\frac{1}{n\cdot\left(n+1\right)\cdot\left(n+2\right)\cdot\left(n+3\right)}\)= \(\frac{1}{3}\left(\frac{1}{n\cdot\left(n+1\right)\left(n+2\right)}-\frac{1}{\left(n+1\right)\cdot\left(n+2\right)\cdot\left(n+3\right)}\right)\)
Giải giúp mình bài này nhé
\(\frac{1}{1.2.3.4}+\frac{1}{2.3.4.5}+\frac{1}{3.4.5.6}+...+\frac{1}{116.117.118.119}\)
Xét tổng S gồm 20 số hạng:
S=\(\frac{1}{1.2.3.4}+\frac{1}{2.3.4.5}+.......+\frac{1}{20.21.22.23}\)
Tính tổng
\(S=\frac{1}{1.2}+\frac{1}{1.2.3}+\frac{1}{1.2.3.4}+.....+\frac{1}{1.2.3.....50}\)
Mọi người giúp mình vs ạ :D
Tính
\(\frac{1}{1.2.3.4}+\frac{1}{2.3.4.5}+...+\frac{1}{47.48.49.50}\)
\(\frac{1}{1.2.3.4}+\frac{1}{2.3.4.5}+\frac{1}{3.4.5.6}+......+\frac{1}{47.48.49.50}\)
bằng mấy nhỉ
1 Thu gọn tổng:
B4=\(\frac{1}{1.2.3.4}+\frac{1}{2.3.4.5}+...+\frac{1}{99.100.101.102}\)
2 tick nha các bạn(HELP ME)
\(y=\frac{1}{1.2.3.4}+\frac{1}{2.3.4.5}+...+\frac{1}{27.28.29.30}\)
A=\(\frac{1}{1.2.3.4}+\frac{1}{2.3.4.5}+......+\frac{1}{7.8.9.10}\)
1 Thu gọn tổng:
B4=\(\frac{1}{1.2.3.4}+\frac{1}{2.3.4.5}+...+\frac{1}{99.100.101.102}\)
2 tick nha các bạn(HELP ME)