Question

chứng minh rằng A=1/10+1/11+1/12+...+1/100>1

Answer 1

Ta có:\(\frac{1}{10}+\frac{1}{11}+...+\frac{1}{100}\)> \(\frac{1}{10}+\left(\frac{1}{100}+\frac{1}{100}+...+\frac{1}{100}\right)\)[ 90 p/s \(\frac{1}{100}\)]

= \(\frac{1}{10}+\frac{90}{100}=\frac{10}{100}+\frac{90}{100}\)=\(\frac{100}{100}=1\)

Vậy \(\frac{1}{10}+\frac{1}{11}+...+\frac{1}{100}\)>1

\(\frac{1}{10}+\frac{1}{11}+...+\frac{1}{100}\)\(\frac{1}{10}+\frac{1}{11}+...+\frac{1}{100}\)