Các câu hỏi tương tự
6 tháng 5 2021 lúc 16:13
chứng minh rằng:\(\dfrac{1}{2^2}\)+\(\dfrac{1}{3^2}\)+\(\dfrac{1}{4^2}\)+...........+<1
\(\dfrac{1}{41}\)+\(\dfrac{1}{42}\)+\(\dfrac{1}{43}\)+..........+\(\dfrac{1}{80}\)>\(\dfrac{7}{12}\)
Chứng minh rằng
a) 1/2 + 1/3 + 1/4 +...+1/63 > 2
b) 1/41 + 1/42 + 1/43 +...+1/79 + 1/80 > 7/12
CM: 41/2×42/2×43/2×.....×80/2=1×3×5×....×79
Chung to
rang:a,1/41+1/42+1/43+....+1/80>1/2 b,1/3+1/3^2+1/3^3+....+1/3^99<1/2
Chứng tỏ rằng:a/ frac{1}{2} frac{1}{41}+frac{1}{42}+frac{1}{43}+...+frac{1}{80} 1b/ 1 frac{3}{10}+frac{3}{11}+frac{3}{12}+frac{3}{13}+frac{3}{14} 2c/ Afrac{1}{2}+frac{1}{2^2}+frac{1}{2^3}+...+frac{1}{2^{100}} 1d/ Bfrac{1}{3}+frac{1}{3^2}+frac{1}{3^3}+...+frac{1}{3^{99}} frac{1}{2}e/ frac{2}{5} frac{1}{41}+frac{1}{42}+frac{1}{43}+...+frac{1}{80} frac{2}{3}f/Cfrac{3}{1^2cdot2^2}+frac{5}{2^2cdot3^2}+frac{7}{3^2cdot4^2}+...+frac{19}{9^2cdot10^2} 1
Đọc tiếp
Chứng tỏ rằng:
a/ \(\frac{1}{2}< \frac{1}{41}+\frac{1}{42}+\frac{1}{43}+...+\frac{1}{80}< 1\)
b/ \(1< \frac{3}{10}+\frac{3}{11}+\frac{3}{12}+\frac{3}{13}+\frac{3}{14}< 2\)
c/ A=\(\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+...+\frac{1}{2^{100}}< 1\)
d/ \(B=\frac{1}{3}+\frac{1}{3^2}+\frac{1}{3^3}+...+\frac{1}{3^{99}}< \frac{1}{2}\)
e/ \(\frac{2}{5}< \frac{1}{41}+\frac{1}{42}+\frac{1}{43}+...+\frac{1}{80}< \frac{2}{3}\)
f/\(C=\frac{3}{1^2\cdot2^2}+\frac{5}{2^2\cdot3^2}+\frac{7}{3^2\cdot4^2}+...+\frac{19}{9^2\cdot10^2}< 1\)
Cmr 1/41+4/42+4/43+.........+1/79+1/80>7/12
CMR 41/2*42/2....80/2=1*3*5...79
Chứng minh rằng:
a)\(\frac{1}{41}+\frac{1}{42}+\frac{1}{43}+...+\frac{1}{79}+\frac{1}{80}>\frac{7}{12}\)
b)\(\frac{1}{2^2}+\frac{1}{2^3}+\frac{1}{2^4}+...+\frac{1}{2^n}<1\)
chứng tỏ rằng :1/41+1/42+1/43+........+2/80>17/12