Cho các số x, y cùng dấu. CM rằng:
a) \(\dfrac{x}{y}+\dfrac{y}{x}\ge2\)
b) \(\left(\dfrac{x^2}{y^2}+\dfrac{y^2}{x^2}\right)-\left(\dfrac{x}{y}+\dfrac{y}{x}\right)\ge0\)
c)\(\left(\dfrac{x^4}{y^4}+\dfrac{y^4}{x^4}\right)-\left(\dfrac{x^2}{y^2}+\dfrac{x^2}{y^2}\right)+\left(\dfrac{x}{y}+\dfrac{y}{x}\right)\ge2\)
Rearrange the word or phrase in the right order to have meaningful sentences
1. she / would not / I / make / so / wish / much / noise /.
→ ………………………………………………………………………………….
2. using / bulbs / energy-saving / about / instead of / 100-watt light bulbs / What /?
→ ………………………………………………………………………………….
3. Last summer, / with / went / Nha Trang / Liz / parents / to / her /.
→ ………………………………………………………………………………….
4. should / playing / not / much / of / free / Children / time / spend / electronic / games / their /.
→ ………………………………………………………………………………….
5. isn’t / , / most / Britney Spears / she / year / singer / this / famous / is / the?
→ ………………………………………………………………………………….