Question

Ajutatima va rog dau coroană
4+8+..........+200

Answer 1

4(1+2+3+....+50)=4*50*51/2=2*50*51=51*100=5100
as simple as that!!!

Answer 2

Pai trebuie sa dam factor comun .

4(1+2....+50) = ?

Acuma ne ocupam de suma ,care se calculeaza cu formula lui gaus =$\frac{n(n+1)}{2}$
     ↓

1+2+....+50 = ?
$\frac{50(50+1)}{2}= 25* 51 =1275$


4(1+2....+50) = 4 · 1275 = 5100