1.Chứng minh a,\(\sqrt{23}\)\(+\)\(\sqrt{15}\)\(< \)\(\sqrt{91}\)b,\(\sqrt{17}\)\(+\)\(\sqrt{26}\)\(+\) \(1\)\(< \)\(\sqrt{99}\)c,\(\frac{1}{6}\)\(< \)\(\frac{1}{5^2}\)\(+\)\(\frac{1}{6^2}\)\(+\)\(\frac{1}{7^2}\)\(+\)\(...\)\(+\)\(\frac{1}{100^2}\)\(< \)\(\frac{1}{4}\)2....
Đọc tiếp
1.Chứng minh
a,\(\sqrt{23}\)\(+\)\(\sqrt{15}\)\(< \)\(\sqrt{91}\)
b,\(\sqrt{17}\)\(+\)\(\sqrt{26}\)\(+\) \(1\)\(< \)\(\sqrt{99}\)
c,\(\frac{1}{6}\)\(< \)\(\frac{1}{5^2}\)\(+\)\(\frac{1}{6^2}\)\(+\)\(\frac{1}{7^2}\)\(+\)\(...\)\(+\)\(\frac{1}{100^2}\)\(< \)\(\frac{1}{4}\)
2. Tính
\(s\)\(=\)\(\left(\frac{-1}{7}\right)\)\(+\)\(\left(\frac{-1}{7}\right)^1+\left(\frac{-1}{7}\right)^2+...+\left(\frac{-1}{7}\right)^{2007}\)
