\(A=3\times\left(1-\frac{1}{5}+\frac{1}{5}-\frac{1}{9}+\frac{1}{9}-\frac{1}{13}+...+\frac{1}{101}-\frac{1}{105}\right)\)
\(A=3\times\left(1-\frac{1}{105}\right)\)
\(A=3\times\frac{104}{105}\)
\(A=\frac{104}{35}\)
\(A=3\times\left(1-\frac{1}{5}+\frac{1}{5}-\frac{1}{9}+\frac{1}{9}-\frac{1}{13}+...+\frac{1}{101}-\frac{1}{105}\right)\)
\(A=3\times\left(1-\frac{1}{105}\right)\)
\(A=3\times\frac{104}{105}\)
\(A=\frac{104}{35}\)
\(C=\frac{5}{1.5}+\frac{5}{5.9}+\frac{5}{9.13}+...+\frac{5}{101.105}\)
\(B=\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}+...+\frac{3}{197.200}\)
\(C=\frac{2}{3.5}+\frac{2}{5.7}+...+\frac{2}{97.99}\)
\(D=\frac{1}{1.5}+\frac{1}{5.9}+\frac{1}{9.13}+...+\frac{1}{101.105}\)
\(E=\frac{1}{3.5}+\frac{1}{5.7}+\frac{1}{7.9}+...+\frac{1}{99.101}\)
\(\frac{3}{1.5}+\frac{3}{5.9}+\frac{3}{9.13}+...+\frac{3}{21.25}\)
Tính tổng:
C=\(\frac{3}{1.5}+\frac{3}{5.9}+\frac{3}{9.13}+...+\frac{3}{101.105}\)
D=\(\frac{4}{2.7}+\frac{4}{7.12}+\frac{4}{12.17}+...+\frac{4}{102.107}\)
E=\(\frac{5}{3.7}+\frac{5}{7.11}+\frac{5}{11.15}+...+\frac{5}{103.107}\)
F=\(\frac{6}{2.7}+\frac{6}{7.12}+\frac{6}{12.17}+...+\frac{6}{102.107}\)
a) B = \(\frac{4}{1.3}+\frac{4}{3.5}+\frac{4}{5.7}+.......+\frac{4}{99.101}\)
b) C = \(\frac{5}{1.5}+\frac{5}{5.9}+\frac{5}{9.13}+......+\frac{5}{101.105}\)
tính nhanh
\(P=\frac{3}{1.5}+\frac{3}{5.9}+\frac{3}{9.13}+...+\frac{3}{197.101}\)
Tính M:
\(\frac{3}{1.5}+\frac{3}{5.9}+\frac{3}{9.13}+.............+\frac{3}{3993.3997}+\frac{3}{3997.4001}\)
CHỨNG TỎ:
\(\frac{1}{101}+\frac{1}{102}+...+\frac{1}{149}+\frac{1}{150}\ge\frac{1}{3}\)
CHÚ Ý:Cái dấu lớn hơn các bạn đừng có tính cái dấu bằng ở dưới nhé
C = \(\frac{2}{4.7}-\frac{3}{5.9}+\frac{2}{7.10}-\frac{3}{9.13}+...+\frac{2}{301.304}-\frac{3}{401.405}\)
tính c