=1/2*2/3*3/4*4/5*5/6=1/6

thank's nha

\(=\frac{1}{2}\frac{2}{3}\frac{3}{4}\frac{4}{5}\frac{5}{6}\frac{6}{7}\frac{7}{8}\frac{8}{9}....\frac{2002}{2003}\frac{2003}{2004}\)

\(=\frac{1}{2004}\)

a, \(\dfrac{1}{2}.\dfrac{1}{4}.\dfrac{1}{6}=\dfrac{1}{48}\)

b, \(\dfrac{1}{2}.\dfrac{1}{4}:\dfrac{1}{6}=\dfrac{1}{8}.6=\dfrac{6}{8}=\dfrac{3}{4}\)

\(a,\dfrac{1}{2}\times\dfrac{1}{4}\times\dfrac{1}{6}=\dfrac{1}{8}\times\dfrac{1}{6}=\dfrac{1}{48}\)

\(b,\dfrac{1}{2}\times\dfrac{1}{4}:\dfrac{1}{6}=\dfrac{1}{8}:\dfrac{1}{6}=\dfrac{6}{8}=\dfrac{3}{4}\)

\(\left(1-\frac{1}{2}\right).\left(1-\frac{1}{3}\right).\left(1-\frac{1}{4}\right).\left(1-\frac{1}{5}\right).\left(1-\frac{1}{6}\right)\)

\(=\frac{1}{2}.\frac{2}{3}.\frac{3}{4}.\frac{4}{5}.\frac{5}{6}\)

\(=\frac{1.2.3.4.5}{2.3.4.5.6}\)

\(=\frac{1}{6}\)

Vậy biểu thức trên có giá trị là \(\frac{1}{6}\)

giá trị biểu thức là 1/6

\(A=\left[\frac{6x^2}{x^3-1}-\frac{2x-2}{x^2+x+1}-\frac{1}{x-1}\right]:\frac{x^2+9}{\left(x-1\right)\left(9-4x\right)}\)

\(=\left[\frac{6x^2}{x^3-1}-\frac{\left(2x-2\right)\left(x-1\right)}{\left(x^2+x+1\right)\left(x-1\right)}-\frac{x^2+x+1}{\left(x-1\right)\left(x^2+x+1\right)}\right]\cdot\frac{\left(x-1\right)\left(9-4x\right)}{x^2+9}\)

\(=\frac{6x^2-\left(2x^2-4x+2\right)-x^2-x-1}{\left(x^2+x+1\right)\left(x-1\right)}\cdot\frac{\left(x-1\right)\left(9-4x\right)}{x^2+9}\)

\(=\frac{5x^2-2x^2+4x-2-x-1}{\left(x^2+x+1\right)}\cdot\frac{\left(9-4x\right)}{x^2+9}\)

\(=\frac{3x^2+3x-3}{\left(x^2+x+1\right)}\cdot\frac{\left(9-4x\right)}{x^2+9}\)

Biểu thức A bạn viết đúng chưa?