Question

se considera functiile f:R->R, f(x)=x+2 si g:R->R, g(x)=2x+3
a) calculati sumaS=g(1)+g(2)+...+g(50)-f(1)-f(2)-...-f(50)
va rog rezolvarea completa ca sa inteleg si eu va multumesc frumos

Answer 1

f(1) +f(2) + f(3) +..........+f(50) = 3+4+5+.......+52 = 52·53/2 - (1+2)= 1375
g(1)+g(2)+g(3) +..........+g(50) = 5 +7 +9+......+103 = (5+2·0) +(5+2·1)+(5+2·2)+....+(5+2.49) = 5·50 + 2(1+2+3+......+49) = 5·50 + 2·49·50/2 =50(5+49) = 50·54 = 2700
S = 2700 - 1375 = 1325