Question

cum se rezolva exercitiul a=2/1*3+2/3*5+...+2/49*51

Answer 1

2 \1 - 2\3 + 2\3 si 2\5 +..+2\49- 2\51 = 2\1 - 2\ 51 |*51

102-2\51 = 100\51

Answer 2

2/1*3=1/1-1/3
2/3*5=1/3-1/5
si asa mai departe  pana la
2/49*51=1/49-1/51
a=1/1-1/3+1/3-1/5+.....+1/49-1/51=
=1/1-1/51=(51-1)/51=50/51