Question

\(A=\frac{1}{1\cdot2}+\frac{1}{3\cdot4}+\frac{1}{5\cdot6}+...+\frac{1}{99\cdot100}\)

CMR 7/12<A<5/6

Answer 1

CM cai j cay

Answer 2

//Chứng minh gì thế=)) < 7/12 hay > 7/12 hay = 7/12

Answer 3

A=1-1/2+1/3-1/4+.....+1/99-1/100

   =(1+1/3+1/5+...+1/99)-(1/2+1/4+...+1/100)

    =(1+1/3+...+1/99)-2(1/2+1/4+...+1/100)

    =(1+1/3+...+1/99)-(1+1/2+...+1/50)

...............TỰ TÍNH TIẾP HEM

=>A=7/12 ĐÚNG KO

Answer 4

7/12 <A<5/6