Question

Sa se afle 2+4+6+8+10+...............+98+100.

Answer 1

2+4+6+8+10+...........+98+100

Inmultim fiecare numar cu 2

2x2+2x4+2x6+2x8+2x10+.........+2x98+2x100

Dam factor comun pe 2 si rezolvam ca o suma a lui  gauss normala

2x(2+4+6+8+10+........+98+100)

2x [(2+100)x100]:2

102x100:1=10200

Sper ca te-am ajutat :)

Ce nu intelegi intreaba :)

Answer 2

2+4+6+8+10+...+98+100=

=2(1+2+3+....+50)=

=2×(50×51)/2=

=50×51=2550