bạn giải cách làm ra nha mk cần gấp lắm nhanh lên ......
bạn giải cách làm ra nha mk cần gấp lắm nhanh lên ......
tính nhanh:
\(\frac{1\cdot2\cdot3+2\cdot4\cdot6+3\cdot6\cdot9+4\cdot8\cdot12}{1\cdot3\cdot4+4\cdot6\cdot8+6\cdot9\cdot12+8\cdot12\cdot16}\)
dấu \(\cdot\)là dấu nhân nha!
\(A=\frac{1}{2\cdot2}+\frac{1}{3\cdot3}+\frac{1}{4\cdot4}+\frac{1}{5\cdot5}+\frac{1}{6\cdot6}+\frac{1}{7\cdot7}+\frac{1}{8\cdot8}+\frac{1}{9\cdot9}\)
HÃY CHỨNG MINH :
\(\frac{2}{5}< A< \frac{8}{9}\)
\(S=\frac{1}{2\cdot2}+\frac{1}{3\cdot3}+\frac{1}{4\cdot4}+\frac{1}{5\cdot5}+\frac{1}{6\cdot6}+\frac{1}{7\cdot7}+\frac{1}{8\cdot8}+\frac{1}{9\cdot9}\)
HÃY CHỨNG MINH \(\frac{2}{5}< S< \frac{7}{8}\)
\(A=\frac{1}{2\cdot2}+\frac{1}{3\cdot3}+\frac{1}{4\cdot4}+\frac{1}{5\cdot5}+\frac{1}{6\cdot6}+\frac{1}{7\cdot7}+\frac{1}{8\cdot8}+\frac{1}{9\cdot9}\)
HÃY CHỨNG MINH \(\frac{2}{5}< S< \frac{7}{8}\)
(\(\frac{1}{1\cdot2}\)+ \(\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+\frac{1}{4\cdot5}+....+\frac{1}{9\cdot10}\)) *10 -x = 10
\(\frac{1}{2\cdot3}\)+\(\frac{1}{3\cdot4}\)+\(\frac{1}{4\cdot5}\)+\(\frac{1}{5\cdot6}\)+\(\frac{1}{6\cdot7}\)+\(\frac{1}{7\cdot8}\)+\(\frac{1}{8\cdot9}\)+ \(\frac{1}{9\cdot10}\)
Tính hộ tôi [Lưu ý : dấu chấm bằng dấu nhân]
Tính nhanh:
\(987654321\cdot\frac{1+1\cdot2+2\cdot3+3\cdot4+4\cdot5+5\cdot6+6\cdot7+7\cdot8+8\cdot9+9\cdot...\cdot999+999\cdot1000+1000}{1000+1000\cdot1001+1001\cdot1002+1002\cdot1003+1003\cdot1004+1004\cdot1005+1005\cdot...\cdot9999+9999\cdot10000+10000}\)
Rút gọn biểu thức sau: \(\frac{1\cdot3\cdot5+2\cdot6\cdot10+3\cdot9\cdot15}{3\cdot5\cdot12+6\cdot10\cdot24+9\cdot15\cdot36}\)
so sánh A và B biết
A=\(\frac{1\cdot2+2\cdot4+3\cdot6+4\cdot8+5\cdot10}{3\cdot4+6\cdot8+9\cdot12+12\cdot16+15\cdot20}\)
B=\(\frac{111111}{666665}\)