Question

giải chi tiết giúp mik với! mik đang cần gấp:

Cho A= 1.3.5.7...49;  B= \(\dfrac{26}{2}.\dfrac{27}{2}...\dfrac{50}{2}\); so sánh A và B

ba bạn nhanh nhất mik sẽ tick cho!

Answer 1

\(A=1\cdot3\cdot5\cdot7\cdot\ldots\cdot49\)

\(=\frac{1\cdot2\cdot3\cdot\ldots\cdot50}{2\cdot4\cdot6\cdot\ldots\cdot50}\)

\(=\frac{1\cdot2\cdot3\cdot\ldots\cdot50}{2\cdot1\cdot2\cdot2\cdot2\cdot3\cdot\ldots\cdot2\cdot25}=\frac{1\cdot2\cdot3\cdot\ldots\cdot50}{2^{25}\cdot\left(1\cdot2\cdot3\cdot\ldots\cdot25\right)}\)

\(=\frac{26\cdot27\cdot\ldots\cdot50}{2^{25}}=\frac{26}{2}\cdot\frac{27}{2}\cdot\ldots\cdot\frac{50}{2}\)