Question

[Vu Ngoc Khang]

Cho:A=1/31+1/32+1/33+..............+1/60

Chứng minh rằngA>7/12

Answer 1

[✓ ℍɠŞ_ŦƦùM $₦G ✓]

\(A=\frac{1}{31}+\frac{1}{32}+\frac{1}{33}+...+\frac{1}{60}\)

\(=\left(\frac{1}{31}+\frac{1}{32}+...+\frac{1}{45}\right)+\left(\frac{1}{46}+...+\frac{1}{60}\right)>\frac{1}{45}.15+\frac{1}{60}.15=\frac{1}{3}+\frac{1}{4}=\frac{7}{12}\)

=>đpcm

l-i-k-e cho mình nha

Answer 2

[Trần Mai Anh]

vì sao lại thế