Question

cum se calculeza 1+ 2+ 3+ 4+ 5 ..............60= ? , dar 1+ 2+ 3= 4 ......100=?

Answer 1

1)
1+2+3+4+5+...........+n=n*(n+1)/2
adica
1+2+3+4+5+..........+60=60*(60+1)/2=30*61=1830
2)
1+2+3+4+..........+n=n*(n+1)/2
adica
1+2+3+............+100=100*(100+1)/2=50*101=5050
Sper ca te-am ajutat!

Answer 2

$\displaystyle1+2+3+4+5+...+60= \frac{60(60+1)}{2} = \frac{60 \cdot 61}{2} = \frac{3660}{2} =1830 \\ \\ \\ 1+2+3+4+...+100= \frac{100(100+1)}{2} = \frac{100 \cdot 101}{2} = \frac{10100}{2} =5050$