Question

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

Answer 1

quá dễ :

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

A=3/2.(1/3-1/5+1/5-1/3+...+1/97-1/99)

A=3/2.(1/3-1/99)

A=3/2.32/99

A= 16/33 

Answer 2

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

A = 3/2 . (1/3 - 1/5 + 1/5 - 1/3 + ... + 1/97 - 1/99)

A = 3/2 . (1/3 - 1/99)

A = 3/2 . 32/99

A = 16/33