\(1-\frac{2}{1.2.2.3:4}-\frac{3}{2.3.3.4:4}-...-\frac{25}{24.25.25.26:4}\)

\(=1-\left(\frac{4}{1.2.3}+\frac{4}{2.3.4}+\frac{4}{3.4.5}+...+\frac{4}{24.25.26}\right)\)

\(=1-2.\left(\frac{1}{1.2}-\frac{1}{2.3}+\frac{1}{2.3}-\frac{1}{3.4}+...+\frac{1}{24.25}-\frac{1}{25.26}\right)\)

\(=1-2\left(\frac{1}{1.2}-\frac{1}{25.26}\right)\)

\(=\frac{1}{325}\)

1/30;-23/57;1031/9;-79993/100;-124;3/25

ủng hộ nha

to noi that: nguoi ta chi thich giup lam bai kho thoi chu bai nay ai di hoc cung lam dc

tai sao ban phai hoi

Phân số tớ kém lắm

Bài làm:

Ta có: \(\frac{9^2.\left(-4\right)^5.72}{5.\left(-6\right)^6}\cdot\frac{6^3.81.\left(-4\right)}{\left(-8\right)^6.3^9}\)

\(=\frac{3^2.-2^{10}.2^3.3^2.2^3.3^3.3^4.-2^2}{5.2^3.3^3.2^{18}.3^9}\)

\(=\frac{2^{18}.3^{11}}{2^{21}.3^{12}.5}\)

\(=\frac{1}{2^3.2.5}=\frac{1}{120}\)

\(\frac{25^5.2^{10}}{20^4.5^4}\)

=\(\frac{25^5.2^{10}}{20^4.25^2}\)

=\(\frac{25^3.2^{10}}{20^4}\)

=\(\frac{25^3.1024}{160000}\)

=\(\frac{25^3.4}{25^2}\)

=\(25.4\)

=100

A=-3.(1-(2/3)²)(1-(2/5)²)...(1-(2/11)²)=-3.(1-2/3)(1+2/3)(1-2/5)(1+2/5)...(1-2/11)(1+2/11)=-3.\(\frac{1}{3}\).\(\frac{5}{3}\).\(\frac{3}{5}\).\(\frac{7}{5}\)...\(\frac{9}{11}.\frac{13}{11}\)

=  -\(\frac{13}{11}\)

\(A=\left(\frac{1^2-2^2}{1^2}\right)\left(\frac{3^2-2^2}{3^2}\right)\left(\frac{5^2-2^2}{5^2}\right)...\left(\frac{\left(2n-1\right)^2-2^2}{\left(2n-1\right)^2}\right)\)

\(=\frac{-1\cdot3}{1^2}\cdot\frac{1\cdot5}{3^2}\cdot\frac{3\cdot7}{5^2}...\cdot\frac{\left(2n-3\right)\left(2n+1\right)}{\left(2n-1\right)^2}=-\frac{1}{1}\cdot\frac{2n+1}{2n-1}=-\frac{2n+1}{2n-1}\)

\({\left[ {{{\left( {\frac{1}{3}} \right)}^2}} \right]^{\frac{1}{4}}}.{\left( {\sqrt 3 } \right)^5} = {\left( {\frac{1}{3}} \right)^{2.\frac{1}{4}}}.{\left( {{3^{\frac{1}{2}}}} \right)^5} = {\left( {{3^{ - 1}}} \right)^{\frac{1}{2}}}{.3^{\frac{1}{2}.5}} = {3^{ - \frac{1}{2}}}{.3^{\frac{5}{2}}} = {3^{ - \frac{1}{2} + \frac{5}{2}}} = {3^2} = 9\)

Chọn D.