Question

Tính tổng: 

A=2/3x5+2/5x7+2/7x9+...+2/97x99

 

 

Answer 1

A = 2/3 x 5+ 2/5 x 7 + 2/7 x 9 + ... + 2/97 x 99

A = 2/3 - 2/99

A = 64/99

Answer 2

A=2/3x5 + 2/5x7 + 2/7x9 + ......+ 2/97x99 = 1/3 - 1/5 + 1/5 - 1/7 + 1/7 - 1/9 + ... + 1/97 - 1/99 
A= 1/3 - 1/99 = 96/3.99 = 32/99 

        Đ/S:tích

Answer 3

A = 2/3 x 5 + 2/ 5 x 7 + 2/7 x 9 + ... + 2/97 x 99

A = 1/3 - 1/99

A = 32/99