题目

World leaders from nearly 200 countries have signed an important historic agreement to fight global climate change. The agreement came after two weeks of talks between the leaders at the 21st Conference in Paris, France. As part of the Paris agreement, countries said they would cut down on pollution However, according to the terms of the deal, countries that don’t do this will not be punished, or fined. Instead，the document is meant to show that governments around the world take climate change seriously and are willing to work together to fight global warming. World leaders have met 13．已知2x≤16且${log_2}x≥\frac{1}{2}$，求函数$f（x）={log_2}\frac{x}{2}•{log_{\sqrt{2}}}\frac{{\sqrt{x}}}{2}$的值域．