ta có:31/2.32.2....60.2=31.32...60/2^30=(31.32.33....60).((1.2.3...30)/2^30.(1.2.3...30)=(1.3.5..59).(2.4.6...60)/(2.4.6...60)=1.3.5...59

Ta biến đổi vế phải thành vế trái:

1.3.5....59=1.3.5...59.\(\frac{2.4.6.....60}{2.4.6.....60}=\frac{1.2.3.4.....60}{\left(1.2.3....30\right).\left(2.2.2.....2\right)}=\frac{31.32......60}{2.2.......2}=\frac{31}{2}.\frac{32}{2}.....\frac{60}{2}\)

Vậy chúng = nhau

=1.48/2.2.2.2.40/2.2.2.56/2.2.2.36/2.2.44/2.2.52/2.2.60/2.2.34/2.38/2.42/2.46/2.50/2.54/2.58/2.31.33...59=1.3.5...59 cần chứng minh

Tớ làm được câu a thôi nhé!

bạn ơi giải rõ ra đc ko?

Ta có: \(\frac{31}{2}.\frac{32}{2}...\frac{60}{2}=\frac{31.32...60}{2^{30}}=31.33...57.59.\left(\frac{32.34...58.60}{2^{30}}\right)\)

                                                                         \(=31.33...57.59.\left(\frac{16.17...29.30}{2^{15}}\right)=17.19...27.29.31.33...57.59.\left(\frac{16.18...30}{2^{15}}\right)\)

\(=17.19...57.59.\left(\frac{8.9...15}{2^7}\right)=9.11.13.15.17...57.59.\left(\frac{8.10.12.14}{2^7}\right)\)

\(=9.11...57.59.\left(\frac{4.5.6.7}{2^3}\right)=5.7.9...57.59.\left(\frac{4.6}{2^3}\right)\)

\(=5.7.9...57.59.3=1.3.5...59\)

\(60!=1\cdot2\cdot3\cdot4\cdot5\cdot...\cdot59\cdot60=1\cdot3\cdot5\cdot...\cdot57\cdot59\times2\cdot4\cdot6\cdot...\cdot58\cdot60\)

\(=1\cdot3\cdot5\cdot...\cdot57\cdot59\times2^{30}\cdot1\cdot2\cdot3\cdot...\cdot30=1\cdot3\cdot5\cdot...\cdot57\cdot59\times2^{30}\times30!\)

\(\Rightarrow1\cdot3\cdot5\cdot...\cdot59=\frac{60!}{30!\times2^{30}}=\frac{31}{2}\cdot\frac{32}{2}\cdot\frac{33}{2}\cdot...\cdot\frac{60}{2}\)đpcm.

\(\frac{31}{2}\cdot\frac{32}{2}\cdot...\cdot\frac{60}{2}\cdot2\cdot4\cdot...\cdot58\cdot60\)

=31.32.33.34...60.1.2.3.4.5...29.30

=1.2.3.4.5.6.7.8.9.10...60

1.3.5.7...59.2.4.6.8...60

=1.2.3.4.5.6...60

Vậy \(\frac{31}{2}\cdot\frac{32}{2}\cdot\frac{33}{2}\cdot...\cdot\frac{60}{2}=1\cdot3\cdot5\cdot...\cdot59\)

\(1.3.5....59=\frac{\left(1.3.5....59\right).\left(2.4.6....60\right)}{2.4.6....60}=\frac{\left(1.2.3.4.5...30\right).31....59.60}{2^{30}.\left(1.2.3...30\right)}=\frac{31.32....60}{2^{30}}=\frac{31}{2}.\frac{32}{2}.\frac{33}{2}...\frac{60}{2}\)

Chị quản lý Sao làm tốt thế mà chẳng được olm công nhận nhỉ

Vì đó là người quản lí nên công nhận cũng có được gì !!!