Question

coroana)))))))))))))))​

Answer 1

Răspuns:

Explicație pas cu pas:

In suma sunt 49-30+1 = 20 termeni

1/49+1/49+...+1/49 < 1/30+1/31+...+1/49 <

 < 1/30 +1/30 +...+1/30

20/49 < 1/30+1/31+...+1/49 < 20/30 = 2/3

1/3 < 20/49, sau  49 < 60, deci :

1/3 < 1/30+1/31+...+1/49 < 2/3