Ta có :
\(1.3.5.7.....199\)
\(=\frac{1.2.3.4.5.6.7.....198.199.200}{2.4.6.....198.200}\)
\(=\frac{\left(1.2.3.....99.100\right)\left(101.102.....200\right)}{\left(1.2.3.....99.100\right)\left(2.2.2.....2.2\right)}\)
\(=\frac{101.102.....200}{2.2.....2}\)
\(=\frac{101}{2}.\frac{102}{2}.....\frac{200}{2}\left(đpcm\right)\)
Chứng minh rằng:
1.3.5.7.9.....197.199=\(\frac{101}{2}+\frac{102}{2}+\frac{103}{2}+...+\frac{200}{2}\)
Chứng tỏ rằng :1.5.7...197.199=\(\frac{101}{2}.\frac{102}{2}.\frac{103}{2}...\frac{200}{2}\)
Chứng tỏ 1.3.5.7.9....197.199=101/2.102/2.103/2....200/2
Chứng tỏ :1.3.5.7.9....197.199=101/2.102/2.103/2.....200/2
chứng minh rằng : 1.3.5.7....197.199 = \(\frac{101}{2}.\frac{102}{2}.\frac{103}{2}....\frac{200}{2}\)
chứng tỏ rằng:1.3.5.7...197.199=101/2.102/2.103/2...200/2
Chứng tỏ rằng 1/101+1/102+1/103+...+1/200>1/2
Chứng tỏ rằng: 1/101+1/102+1/103+......+1/200 > 1/2
CMR: 1.3.5.7......197.199=\(\frac{101}{2}+\frac{102}{2}+\frac{103}{2}+........+\frac{200}{2}\)
