Question

1.

a, So sánh tổng A= 1/12+ 1/13+ 1/14+ 1/15+ 1/16+ 1/17 với 1/2

b, So sánh 53/57 và 531/571

 

Giải giúp e với anh chị

E cảm ơn nhìu

Answer 1

A=\(\frac{1}{12}\)+\(\frac{1}{13}\)+\(\frac{1}{14}\)+\(\frac{1}{15}\)+\(\frac{1}{16}\)+\(\frac{1}{17}\)

A< \(\frac{1}{12}\)+\(\frac{1}{12}\)+\(\frac{1}{12}\)+\(\frac{1}{12}\)+\(\frac{1}{12}\)+\(\frac{1}{12}\)

A<6.\(\frac{1}{12}\)

A<\(\frac{1}{2}\)

Vậy A<\(\frac{1}{2}\)

 

Answer 2

b.\(\frac{53}{57}\)=1-\(\frac{4}{57}\)=1-\(\frac{40}{570}\)

\(\frac{531}{571}\)=1-\(\frac{40}{571}\)

Ta có:\(\frac{40}{570}\)>\(\frac{40}{571}\)=> 1-\(\frac{40}{570}\)<1-\(\frac{40}{571}\)=>\(\frac{53}{57}\)<\(\frac{531}{571}\)

 

Answer 3

#A=1/2

#Linh