Question

Tính S/P biết:

S = 1/2 + 1/3 + 1/4 + 1/5 + ... + 1/49 + 1/50

P = 1/49 + 2/48 + 3/47 + ... + 48/2 +49/1

Answer 1

So sánh tổng : S = 1/5 + 1/9 + 1/10 + 1/41 + 1/42 với 1/2

Answer 2

S=

=50/50+50/49+50/48+...+50/2

=50.(1/50+1/49+1/48+...+1/4+1/3+1/2)

=50

P=

P=(1/49+1)+(2/48+1)+...+(48/2+1)+1

P= 50/49+50/48+....+50/2+50/50=1

vậy s/p = 1/50