Tính các tổng sau:
a) \(\frac{1}{7}+\frac{1}{7^2}+\frac{1}{7^3}+...+\frac{1}{7^{100}}.\)
b) \(-\frac{4}{5}+\frac{4}{5^2}-\frac{4}{5^3}+...+\frac{4}{5^{200}}.\)
c)\(\frac{-1}{3}+\frac{1}{3^2}-\frac{1}{3^3}+...+\frac{1}{3^{100}}-\frac{1}{3^{101}}\)
Tính
A = \(\frac{1}{7}+\frac{1}{7^2}+\frac{1}{7^3}+...+\frac{1}{7^{100}}\)
B = \(\frac{4}{5}+\frac{4}{5^2}-\frac{4}{5^3}+...+\frac{4}{5^{200}}\)
1.So sánh A và B:
\(A=\frac{10^{11}-1}{10^{12}-1}\)
\(B=\frac{10^{10}+1}{10^{11}+1}\)
2.tính tổng
A=1+2+22+...+2100
B=3-32+33-3+...+399-3100
C1+52+54+56+...+5200
D=7-74+77+...+7301
E=\(\frac{1}{7}+\frac{1}{7^2}+\frac{1}{7^3}+...+\frac{1}{7^{100}}\)
F=\(0-\frac{4}{\text{5}}+\frac{4}{\text{5}^2}-\frac{4}{\text{5}^3}+...+\frac{4}{\text{5}^{200}}\)
Tinh cac tong sau
\(H=\frac{1}{7}+\frac{1}{7^2}+\frac{1}{7^3}+...+\frac{1}{7^{100}}\)
\(I=\frac{4}{5}+\frac{4}{5^2}+\frac{4}{5^3}+...+\frac{4}{5^{200}}\)
\(A=\frac{3}{7}-\frac{3}{17}+\frac{3}{37}:\frac{5}{7}-\frac{5}{17}+\frac{5}{37}\) + \(\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}:\frac{7}{5}-\frac{7}{4}-\frac{7}{3}-\frac{7}{2}\)
Tính hợp lí nha:
(Dấu : là phần nha)
Làm ơn giúp mình nha
Bài 1: tính nhanh
a)\(\frac{5}{7}.\frac{-7}{9}-\frac{5}{7}.\frac{2}{9}-\frac{5}{9}\)
b)\(\left(3\frac{1}{13}+2\frac{1}{4}\right)-2\frac{2}{13}\)
c)\(\frac{3}{15}.\frac{3}{7}-\frac{1}{5}.\frac{4}{-7}+\frac{4}{5}\)
giúp mình nha!
Tính
\(\frac{\left(13\frac{1}{4}-2\frac{5}{27}-10\frac{5}{6}\right).230\frac{1}{25}+46\frac{3}{4}}{\left(1\frac{3}{7}+\frac{10}{3}\right):\left(12\frac{1}{3}-14\frac{2}{7}\right)}\)
Ai làm nhanh đúng mk tick nha !
\(\frac{\frac{2}{5}-\frac{2}{9}+\frac{2}{11}}{\frac{7}{5}-\frac{7}{9}+\frac{7}{11}}:\frac{\frac{1}{3}-\frac{1}{4}+\frac{1}{5}}{\frac{7}{6}-\frac{7}{8}+\frac{7}{10}}\)
tính hợp lý giúp mình với
tính :
A = \(\frac{\frac{3}{7}-\frac{3}{17}+\frac{3}{37}}{\frac{5}{7}-\frac{5}{17}+\frac{5}{37}}\)+\(\frac{\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{5}}{\frac{7}{5}-\frac{7}{4}+\frac{7}{3}-\frac{7}{2}}\)