Question

S = 1/11+1/12+1/13+1/14+1/15+1/16+1/17+1/18+1/19+1/20

tìm S và so sánh S với 1/2

Answer 1

\(S=\frac{1}{11}+\frac{1}{12}+\frac{1}{13}+\frac{1}{14}+\frac{1}{15}+\frac{1}{16}+\frac{1}{17}+\frac{1}{18}+\frac{1}{19}+\frac{1}{20}>\frac{1}{20}+...+\frac{1}{20}\)(10 số \(\frac{1}{20}\))

=\(\frac{1}{20}.10=\frac{1}{2}\)

vậy S>1/2

Answer 2

vậy 1/2 = 1/2 vì ( S = 1/20 )