Question

aratati ca 1 pe 2 + 1pe 4 + 1 pe 6 + 1 pe 8 +..............+ 1 pe 100 mai mic decat 25

Answer 1

1/2
1/4<1/2
1/6<1/2
1/8<1/2
....
1/100<1/2
avem 50 termeni         [explicatie(100-2)/2+1=49+1=50]
1/2+1/4+1/6+1/8+...1/100<1/2×50
1/2+1/4+1/6+1/8+...1/100<25