Question

Chứng minh rằng

\(\frac{1.3.5.7....39}{21.22.23....40}=\frac{1}{2^{20}}\)

Answer 1

\(\frac{1.3.5.7...39}{21.22.23...40}=\frac{\left(2.4.6.8...40\right).\left(1.3.5.7...39\right)}{\left(2.4.6.8...40\right).\left(21.22.23...40\right)}=\frac{1.2.3.4...40}{^{2^{20}.1.2.3.4...40}}=\frac{1}{2^{20}}\)

Answer 2

\(\frac{1.3.5.7....39}{21.22.23....40}=\frac{\left(2.4.6....40\right).\left(1.3.5.7....39\right)}{\left(2.4.6....40\right).\left(21.22.23...40\right)}=\frac{1.2.3.4....40}{2^{20}.1.2.3.4....40}=\frac{1}{2^{20}}\)