CMR: 1/101 + 1/102 + 1/203 + ... + 1/200 > 13/14
CMR: 1/101 + 1/102 + 1/203 + ... + 1/200 > 13/14
CMR:
a, 101 x 102 x 103 x..x 200 chia hết cho 1 x 3 x 5 x...x 199.
b, 201 x 202 x 203 x...x 600 chia hết cho 3200
CMR: 1-1/2+1/3-1/4+....+1/199-1/200=1/101-1/102+...+1/200
CMR :: 1-1/2+1/3-1/4+.....+1/199-1/200 =1/101+1/102+...+1/200
cmr : -1/2 + 1/3 + -1/4 + ..... + 1/199 + -1/200 = 1/101 + 1/102 + .... + 199 + 1/200
CMR:1/101+1/102+1/103+...+1/200=1-1/2+1/3-1/4+...+1/199-1/200
Xét vế phải\(1-\frac{1}{2}+\frac{1}{3}-\frac{1}{4}+.....+\frac{1}{199}-\frac{1}{200}\)
=\(\left(1+\frac{1}{3}+\frac{1}{5}+..+\frac{1}{199}\right)-\left(\frac{1}{2}+\frac{1}{4}+...+\frac{1}{200}\right)\)
=\(\left(1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+...+\frac{1}{199}+\frac{1}{200}\right)-2.\left(\frac{1}{2}-\frac{1}{4}-...-\frac{1}{200}\right)\)
=\(1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+\frac{1}{5}+...+\frac{1}{199}+\frac{1}{200}-1-\frac{1}{2}-...-\frac{1}{100}\)
=\(\frac{1}{101}+\frac{1}{102}+...+\frac{1}{200}\)
CMR : ( 1 + 1/3 + 1/5 + ...+ 1/99 ) + ( 1/2 + 1/4+ ..1/200 ) = 1/101 + 1/102+..+1/200
P/s : Đề sai mik sửa lại rồi : Tham khảo nhé :
\(\left(1+\frac{1}{3}+\frac{1}{5}+...+\frac{1}{199}\right)-\left(\frac{1}{2}+\frac{1}{4}+...+\frac{1}{200}\right)\)
\(=\left(1+\frac{1}{2}+\frac{1}{3}+...+\frac{1}{199}+\frac{1}{200}\right)-2\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{6}+...+\frac{1}{200}\right)\)
\(=\left(1+\frac{1}{2}+\frac{1}{3}+...+\frac{1}{199}+\frac{1}{200}\right)-\left(1+\frac{1}{2}+\frac{1}{3}+...+\frac{1}{100}\right)\)
\(=\frac{1}{101}+\frac{1}{102}+...+\frac{1}{200}\)
\(1+\frac{1}{3}+\frac{1}{5}+...+\frac{1}{99}-\left(\frac{1}{2}+\frac{1}{4}+...+\frac{1}{200}\right)\)
\(=1+\frac{1}{2}+\frac{1}{3}+....+\frac{1}{200}-2.\left(\frac{1}{2}+\frac{1}{4}+....+\frac{1}{200}\right)\)
\(=1+\frac{1}{2}+\frac{1}{3}+....+\frac{1}{200}-1+\frac{1}{2}+....+\frac{1}{100}\)
\(=\frac{1}{101}+\frac{1}{102}+...+\frac{1}{200}\)
CMR: 1-1/2+1/3-1/4+...+1/199-1/200=1/101+1/102+1/103+...+1/200
CMR:
1-1\2+1\3-1\4+.....+1\199-1\200=1\101+1\102+.....+1\200