Question

calculati 1+3+5+....+63

Answer 1

Răspuns:

Explicație pas cu pas:

S = 1 + 3 + 5 + .....+ 63

-> stabilesc cati termeni are suma, cu ratia = 2

( 63 - 1) : 2 + 1 = 62 : 2 + 1 = 32 termeni are suma

S = 32 × ( 1 + 63) : 2

S = 32 × 64 : 2

S = 32 × 32

S = 1 024

Answer 2

Răspuns:

Explicație pas cu pas:

1 + 3 + 5 +...+ 63 =?

S = 1 + 3 + 5 +...+ 63

S = 63 +...+ 5 + 3 + 1

_______________

2S = 64 × ?

1 = 2 × 0 + 1

3 = 2 × 1 + 1

5 = 2 × 2 + 1

...

63 = 2 × 31 + 1

___________

31-0+1 = 32 termeni

2S = 64 × 32

2S = 2 048

S = 2S : 2

S = 2 048 : 2

S = 1 024