Question

8+16+24+32+...+4000 calculati

Answer 1

scoti 8 factor si ai:

8(1+2+3+4+...+500)=8*(500*501/2)=8*(250*501)=8*125250=1002000

Answer 2

$\displaystyle 8+16+24+32+...+4000 =8(1+2+3+...+500)= \\ \\ =8 \times \frac{500(500+1)}{2} =8 \times \frac{500 \times 501}{2} =8 \times \frac{250500}{2} = \\ \\ =8 \times 125250=1002000$