\(\frac{51.52....100}{2^{50}}=\frac{\left(51.52....100\right)\left(1.2.3...50\right)}{2^{50}.\left(1.2.3...50\right)}=\frac{1.2.3....100}{\left(1.2\right)\left(2.2\right).\left(2.3\right)...\left(2.50\right)}=\frac{1.2.3...100}{2.4.6...100}=1.3...99\) (đpcm)
P/s: . là dấu nhân