Các câu hỏi tương tự
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 : a) 1/41 + 1/42 + 1/43 +...+ 1/80 < 5/6
b) 1/2^2 + 1/2^4 + 1/2^6 +...+ 1/2^200 < 1/3
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
NY
6 tháng 5 2021 lúc 16:13
chứng minh rằng:\(\dfrac{1}{2^2}\)+\(\dfrac{1}{3^2}\)+\(\dfrac{1}{4^2}\)+...........+<1
\(\dfrac{1}{41}\)+\(\dfrac{1}{42}\)+\(\dfrac{1}{43}\)+..........+\(\dfrac{1}{80}\)>\(\dfrac{7}{12}\)
CM: 41/2×42/2×43/2×.....×80/2=1×3×5×....×79
chung to :1/41+1/42+1/43+.....+1/80>7/12
Hãy chứng tỏ rằng:
a) 1/41+1/42+1/43+...+1/79+1/80>7/12
b)11/15<1/21+1/22+1/23+...+1/59+1/60<3/2
hãy chứng tỏ rằng : 1/41 + 1/42 + 1/43 + ... + 1/80 > 3/5
a)frac{1}{5^2}+frac{1}{5^3}+frac{1}{5^4}+......+frac{1}{5^{2019}} frac{1}{2}b) frac{1}{2^2}+frac{1}{3^3}+frac{1}{4^3}+......+frac{1}{4^2} 1c) frac{1}{2}-frac{1}{4}+frac{1}{8}-frac{1}{16}+frac{1}{32}-frac{1}{64} frac{1}{3}d) frac{1}{3}+frac{2}{3^2}+frac{3}{3^3}-frac{4}{3^4}+......+frac{99}{3^{99}}-frac{100}{3^{100}} frac{3}{16}e) frac{1}{41}+frac{1}{42}+frac{1}{43}+frac{1}{44}+.....+frac{1}{79}+frac{1}{80}frac{7}{12} M.n ơi giúp mình với ạmình đang cần gấp
Đọc tiếp
a)\(\frac{1}{5^2}+\frac{1}{5^3}+\frac{1}{5^4}+......+\frac{1}{5^{2019}}< \frac{1}{2}\)
b) \(\frac{1}{2^2}+\frac{1}{3^3}+\frac{1}{4^3}+......+\frac{1}{4^2}< 1\)
c) \(\frac{1}{2}-\frac{1}{4}+\frac{1}{8}-\frac{1}{16}+\frac{1}{32}-\frac{1}{64}< \frac{1}{3}\)
d) \(\frac{1}{3}+\frac{2}{3^2}+\frac{3}{3^3}-\frac{4}{3^4}+......+\frac{99}{3^{99}}-\frac{100}{3^{100}}< \frac{3}{16}\)
e) \(\frac{1}{41}+\frac{1}{42}+\frac{1}{43}+\frac{1}{44}+.....+\frac{1}{79}+\frac{1}{80}>\frac{7}{12}\)
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