A = 1/5 + 1/13 + 1/14 + 1/15 + 1/60 + 1/61 + 1/62 + 1/63
Ta có : A = 1/5 + 1/13 + 1/14 + 1/15 + 1/60 + 1/61 + 1/62 + 1/63 < 1/5 + 1/12 + 1/12 + 1/12 + 1/60 + 1/60 + 1/60
= A < 1/5 + 1/4 + 1/20
= A < 1/2
Vậy A < 1/12
Chứng minh rằng \(S=\frac{1}{5}+\frac{1}{13}+\frac{1}{14}+\frac{1}{15}+\frac{1}{61}+\frac{1}{62}+\frac{1}{63}
Chung to A=\(\frac{1}{5}+\frac{1}{13}+\frac{1}{14}+\frac{1}{15}+\frac{1}{61}+\frac{1}{62}+\frac{1}{63}<\frac{1}{2}\)
so sánh D với 1 phần 2:
D=\(\frac{1}{5}+\frac{1}{13}+\frac{1}{14}+\frac{1}{15}+\frac{1}{61}+\frac{1}{62}+\frac{1}{63}\)
Cho S=\(\frac{1}{5}\)+\(\frac{1}{13}\)+\(\frac{1}{14}\)+\(\frac{1}{15}\)+\(\frac{1}{61}\)+\(\frac{1}{62}\)+\(\frac{1}{63}\)
Chứng minh S<\(\frac{1}{2}\)
Ai học lớp 6 trở lên mà ko làm được thì về Tiểu học học lại.
Chứng minh :
\(S=\frac{1}{5}+\frac{1}{13}+\frac{1}{14}+\frac{1}{15}+\frac{1}{61}+\frac{1}{62}+\frac{1}{63}\)< \(\frac{1}{2}\)
chứng minh rằng:a/ \(\frac{1}{4}+\frac{1}{16}+\frac{1}{36}+\frac{1}{64}+\frac{1}{100}+\frac{1}{144}+\frac{1}{196}< \frac{1}{2}\) \(\frac{1}{2}\)
b/\(\frac{1}{5}+\frac{1}{13}+\frac{1}{14}+\frac{1}{15}+\frac{1}{61}+\frac{1}{62}+\frac{1}{63}< \frac{1}{2}\)\(\frac{1}{2}\)
nhanh thì tích
chậm thì thôi
So sánh \(A=\frac{1}{5}+\frac{1}{13}+\frac{1}{14}+\frac{1}{15}+\frac{1}{61}+\frac{1}{62}+\frac{1}{63}\)VÀ \(B=\frac{1}{2}\)
chứng minh: S= \(\frac{1}{5}\)+\(\frac{1}{13}\)+\(\frac{1}{14}\)+\(\frac{1}{15}\)+\(\frac{1}{61}\)+\(\frac{1}{62}\)+\(\frac{1}{63}\)<\(\frac{1}{2}\)
Chứng minh:
S=\(\frac{1}{5}\)+\(\frac{1}{13}\)+\(\frac{1}{14}\)+\(\frac{1}{15}\)+\(\frac{1}{61}\)+\(\frac{1}{62}\)+\(\frac{1}{63}\)<\(\frac{1}{2}\)
