user-avatar
goldenf
6 năm trước

Chứng minh rằng: \(\dfrac{3}{2^2}+\dfrac{5}{6^2}+\dfrac{7}{12^2}+\dfrac{9}{20^2}+...+\dfrac{19}{90^2}< 1\)

Thích Trả lời Chia sẻ

Các câu hỏi liên quan

Bài 1: Tính:

A=\(\left(-2\right).\left(-3\right)-5.\left|-5\right|+125.\left(\dfrac{-1}{5}\right)^2\)

B=\(\left(-3\right).\left|-7\right|-\left(-4\right).\left|5\right|+\dfrac{1}{3}.\left|-9\right|\)

C=\(\left(-2\right)^3.\left|-3\right|-\dfrac{1}{5}.\left|-25\right|-4.\left|-7\right|+\left(-2\right)^2\)

D=\(\left(-6\right).\left|-3\right|+2.\left|-9\right|-7\left|\left(-2\right)^3\right|+8.\left|-7\right|\)

E=\(\left|-3^2\right|.\left|4\right|-\left|7\right|.8-\left|6\right|.\left|-8\right|-\left|12\right|.\left(\dfrac{1}{2}\right)^2\)

Bài 2: Tìm x:

a)\(12-2\left|3x+2\right|=10\)

b)\(2.\left|5-4x\right|+17=\left(-2\right)^3.\left(-4\right)\)

c)\(\left|3x-5\right|+\left(-3\right)^2.2=12.\left|3x+5\right|+117\)

d)\(4.\left|3-2x\right|+\left(-5\right).\left|4-3x\right|-5=-6\)

e)\(\left|2x-7\right|-2^3.\left|2x-7\right|+15=-5.\left|2x-7\right|+3\)

f)\(\left|x+2\right|+\left|x^2-4\right|=0\)

g)\(\left|3x-9\right|+\left|x^2-9\right|=0\)

h)\(\left|2x-1\right|+\left|x^2-\dfrac{1}{4}\right|=0\)
2018 © Loga - Không Ngừng Sáng Tạo - Bùng Cháy Đam Mê
Loga Team