B = 1 1.2.3.4 + 1 2.3.4.5 + 1 3.4.5.6 + ... + 1 27.28.29.30 = 1 3 1 1.2.3 − 1 2.3.4 + 1 2.3.4 − 1 3.4.5 + ... + 1 27.28.29 − 1 28.29.30 = 1 3 1 1.2.3 − 1 28.29.30 = 1353 8120
B = 1 1.2.3.4 + 1 2.3.4.5 + 1 3.4.5.6 + ... + 1 27.28.29.30 = 1 3 1 1.2.3 − 1 2.3.4 + 1 2.3.4 − 1 3.4.5 + ... + 1 27.28.29 − 1 28.29.30 = 1 3 1 1.2.3 − 1 28.29.30 = 1353 8120
tính giá trị biểu thức: 1/1.2.3.4 + 1/2.3.4.5 + 1/3.4.5.6 +...+1/27.28.29.30
tính
a) 2/3.5+2/5.7+2/7.9+2/9.11+2/11.13
b) 1/1.2.3.4+1/2.3.4.5+1/3.4.5.6+1/27.28.29.30
bài1Tính a,B=1/1.2.3.4+1/2.3.4.5+1/3.4.5.6+...+1/27.28.29.30
b,1.2.3+2.3.4+3.4.5+...+48.49.50
Tính giá trị biểu thức :
a) 1/1.2.3 + 1/2.3.4 + 1/3.4.5 + ...... + 1/27.28.29
b) 1/1.2.3.4 + 1/2.3.4.5 + 1/3.4.5.6 + ..... + 1/27.28.29.30
Khẩn cấp nhé
1 tinh
a/ 1/1.2.3+1/2.3.4+1/3.4.5+...+1/98.99.100
b/ 1/1.2.3.4+1/2.3.4.5+1/3.4.5.6+...+1/27.28.29.30
tính tổng : 1/1.2.3.4 + 1/2.3.4.5 +....+1/27.28.29.30 =
tính nhanh
A= \(\frac{1}{1.2.3.4}\)+\(\frac{1}{2.3.4.5}\)+\(\frac{1}{3.4.5.6}\)+.........+\(\frac{1}{27.28.29.30}\)
Tính F = 1/1.2.3.4 +1/2.3.4.5+1/3.4.5.6+....+1/47.48.49.50
P = 1/1.2.3.4 + 1/2.3.4.5 + 1/3.4.5.6 + ... + 1/97.98.99.100
Hãy tính giá trị biếu thức P.3.98.99
1/1.2.3.4+1/2.3.4.5+......+1/27.28.29.30
mn giải giúp mik nhé mik tik cho