Ta có: 1/9 + 1/10 < 1/8+1/8 = 1/4
1/41+1/42< 1/40+1/40=1/20
=> 1/5+1/9+1/10+1/41+1/42<1/5+1/4+1/20=1/2
Vậy 1/5+1/9+1/10+1/41!+1/42<1/2
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So sánh: \(S=\frac{1}{5}+\frac{1}{9}+\frac{1}{10}+\frac{1}{41}+\frac{1}{42}\)với \(\frac{1}{2}\)
Cho B = \(\frac{1}{5}+\frac{1}{9}+\frac{1}{10}+\frac{1}{41}+\frac{1}{42}\)
So sánh B với \(\frac{1}{2}\)
SO SÁNH :S=\(\frac{1}{5}\)+\(\frac{1}{9}\)+\(\frac{1}{10}\)+\(\frac{1}{41}\)+\(\frac{1}{42}\)với \(\frac{1}{2}\)
So sánh tổng S=\(\frac{1}{5}\)+\(\frac{1}{9}\)+\(\frac{1}{10}\)+\(\frac{1}{41}\)+\(\frac{1}{42}\) với \(\frac{1}{2}\)
1. so sánh
A=\(\frac{1}{2^2}+\frac{1}{3^2}+\frac{1}{4^2}+....+với1\)
B=\(1-\left(\frac{1}{5}+\frac{1}{13}+\frac{1}{25}+\frac{1}{41}+\frac{1}{61}+\frac{1}{85}+\frac{1}{113}\right)với\frac{1}{2}\)
C=\(1-\left(\frac{1}{5}+\frac{1}{11}+\frac{1}{10}+\frac{1}{9}+\frac{1}{59}+\frac{1}{58}+\frac{1}{57}\right)với\frac{1}{2}\)
So sanh S=\(\frac{1}{5}+\frac{1}{9}+\frac{1}{10}+\frac{1}{40}+\frac{1}{42}voi\frac{1}{2}\)
minh can cach lam
ai nhanh minh tick
Tính tỏng\(B=\frac{1}{1.2.3}+\frac{1}{2.3.4}+\frac{1}{3.4.5}+...+\frac{1}{37.38.39}\)
\(A=\frac{1}{41}+\frac{1}{42}+...+\frac{1}{80}\) so sánh a với \(\frac{7}{42}\)
So sánh :
a)\(\frac{3}{124},\frac{1}{41},\frac{5}{207},\frac{2}{83}\)
b)\(\frac{-2525}{2929}và\frac{-217}{245}\)
c)\(A=\frac{3^{10}+1}{3^9+1}vàB=\frac{3^9+1}{3^8+1}\)
d)\(\frac{27}{82}và\frac{26}{75}\)
So sánh A với 1.
Biết: \(A=\frac{1}{2!}+\frac{2}{3!}+\frac{3}{4!}+\frac{4}{5!}+...+\frac{8}{9!}+\frac{9}{10!}\)