Va rog!Dau coroana!Si 20 puncte.

2/1*2 + 2+4/2*3 + 2+4+6/3*4 + ... + 2+4+6+...+100/50*51 = 2/2 + 6/6 + 12/12 + ... + 2550/2550 = 1 + 1 + 1 + ... + 1 } * 100 / 2 = 1 + 1 + 1 + ... + 1 } *50 = 1 * 50 = 50