\(\frac{3^2}{20.23}+\frac{3^2}{23.26}+...+\frac{3^2}{77.80}<\frac{1}{8}\)
\(=3\left(\frac{1}{20.23}+\frac{1}{23.26}+...+\frac{1}{77.80}\right)\)
\(=3\left(\frac{1}{20}-\frac{1}{23}+\frac{1}{23}-\frac{1}{26}+...+\frac{1}{77}-\frac{1}{80}\right)\)
\(=3\left(\frac{1}{20}-\frac{1}{80}\right)\)
\(=3.\frac{3}{80}=\frac{9}{80}\)
\(\Rightarrow\frac{9}{80}=\frac{1}{8}\)
Chứng minh
\(\frac{3^2}{20.23}+\frac{3^2}{23.26}+...+\frac{3^2}{77.80}\) <1
Chứng minh rằng: \(\frac{3^2}{20.23}+\frac{3^2}{23.26}+...+\frac{3^2}{77.80}<1\)
Chứng minh rằng \(\frac{3^2}{20.23}+\frac{3^2}{23.26}+...+\frac{3^2}{77.80}< 1\)
so sánh \(\frac{3^4}{20.23}+\frac{3^4}{23.26}+...+\frac{3^4}{77.80}\) với 1
Chứng minh rằng:
\(\frac{3^2}{20.23}\)+ \(\frac{3^2}{23.26}\)+ ... + \(\frac{3^2}{77.80}\)< 1
Làm đi mình tick cho :3
Chứng minh rằng
\(\frac{1}{20.23}+\frac{1}{23.26}+\frac{1}{26.29}+...+\frac{1}{77.80}< \frac{1}{9}\)
Chứng minh: 3^2/20.23+3^2/23.26+...+3^2/77.80<1/8
\(\frac{3^2}{20.23}\)+ \(\frac{3^2}{23.26}\)+ ...................... + \(\frac{3^2}{77.80}\)so sánh với 1
Các bạn giúp mình nhé !
\(B=\frac{9}{20.23}+\frac{9}{23.26}+\frac{9}{26.29}+....+\frac{9}{77.80}\)