TÍNH A=(3/4-81)(3^2/5-81)(3^3/6-81)...(3^2013/2016-81)
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Ta có
\(A=\left(\frac{3}{4}-81\right)\left(\frac{3^2}{5}-81\right)...\left(\frac{3^6}{9}-81\right)...\left(\frac{3^{2013}}{2016}-81\right)=\left(\frac{3}{4}-81\right)\left(\frac{3^2}{5}-81\right)...\left(\frac{729}{9}-81\right)...\left(\frac{3^{2013}}{2016}-81\right)=0\)
vì 729/9=81
Vậy A=0
k me đi
\(\left(\frac{3}{4}-81\right).\left(\frac{3^2}{5}-81\right).\left(\frac{3^3}{6}-81\right).\left(\frac{3^4}{7}-81\right).\left(\frac{3^5}{8}-81\right).\left(\frac{729}{9}-81\right)....\left(\frac{3^{2013}}{2016}-81\right)\)
=>....................................................................................................................(81-81)..............................................
=>.....................................................................................................................0.....................................................
=>A=0
theo bài ra ta có:
\(C=\left(\frac{3}{4}-81\right)\left(\frac{3^2}{5}-81\right)\left(\frac{3^3}{6}-81\right)...\left(\frac{3^{2013}}{2016}-81\right)\)
C = \(\left(\frac{3}{4}-81\right)...\left(\frac{3^6}{9}-81\right)...\left(\frac{3^{2013}}{2016}-81\right)\)
\(C=\left(\frac{3}{4}-81\right)...\left(81-81\right)...\left(\frac{3^{2013}}{2016}-81\right)\)
C = \(\left(\frac{3}{4}-81\right)...0...\left(\frac{3^{2013}}{2016}-81\right)\)
C = 0
vậy C = 0
Đặt \(A=\left(\dfrac{3}{4}-81\right)\left(\dfrac{3^2}{5}-81\right)\left(\dfrac{3^3}{6}-81\right)\cdot...\cdot\left(\dfrac{3^{2000}}{2003}-81\right)\)
\(=\left(\dfrac{3^6}{9}-81\right)\cdot\left(\dfrac{3}{4}-81\right)\left(\dfrac{3^2}{5}-81\right)\cdot...\cdot\left(\dfrac{3^{2000}}{2003}-81\right)\)
\(=\left(81-81\right)\cdot\left(\dfrac{3}{4}-81\right)\left(\dfrac{3^2}{5}-81\right)\cdot...\cdot\left(\dfrac{3^{2000}}{2003}-81\right)\)
=0