Răspuns:
(2/1*3 + 2/3*5+2/5*7 +....2/97*99) - (1/1*2 + 1/ 2*3 +....... 1/98*99)=
= (3-1/1*3+5-3/ 3*5 +...+ 99-97 /97*99)-(2-1/1*2+ 3-2/2*3+... 99-98/98*99)=
=((3/1*3- 1/1*3 ) +(5/3*5-3/3*5) +...(99/97*99-97/97*99 )) - (( 2/1*2-1/1*2 )+...+(99/98*99-98/98*99))=
= 1/1-1/3 + 13-1/5+......+1/98-1/99=
=1/1+ 1/99 =
=99/99 +1/99=
=100/99
Explicație pas cu pas:
