1/2(1/1.2-1/2.3+1/2.3-1/3.4+........+1/37.38-1/38.39)
=1/2(1/1.2-1/38.39)
=1/2.370/741
=158/741
Đúng 0
Bình luận (0)
Các câu hỏi tương tự
1/1.2.3+1/2.3.4+1/3.4.5+...+1/37.38.39
1/1.2.3+1/2.3.4+1/3.4.5+....+1/37.38.39 = ?
1/1.2.3+1/2.3.4+1/3.4.5+...+1/37.38.39
1/1.2.3+1/2.3.4+1/3.4.5+...+1/37.38.39
Tính tổng A= 1/1.2.3 +1/2.3.4+1/3.4.5+.......+1/37.38.39
tinhs
1/1.2.3+1/2.3.4+1/3.4.5+............+1/37.38.39
tinh A= 1/1.2.3 + 1/2.3.4 +1/3.4.5 + ... +1/36.37.38 +1/ 37.38.39
Tính nhanh\(\frac{1}{1.2.3}+\frac{1}{2.3.4}+\frac{1}{3.4.5}+...+\frac{1}{37.38.39}\)
Tính:
\(\frac{1}{1.2.3}+\frac{1}{2.3.4}+\frac{1}{3.4.5}+...+\frac{1}{37.38.39}\)