题目内容
已知sinα＞sinβ，那么下列命题成立的是（）。
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案例分析题Despite the brouhaha (骚动) over stolen e-mails from the University of East Anglia, the science of climate change is well enough established by now that we can move on to the essential question: what’s the damage going to be The total bill, if emissions are left unchecked, could reach 20 percent of annual per capita income, says Nicholas Stern, the British economist who led an influential Whitehall-sponsored study. William Nordhaus, a Yale economist, puts his "best guess" at 2.5 percent of yearly global GDP. And according to Dutch economist Richard Tol, the economic impact of a century’s worth of climate change is "relatively small" and "comparable to the impact of one or two years of economic growth." These estimates aren’t just different—they’re different by an order of magnitude. And while some might dismiss the cost estimates as mere intellectual exercises, they’re intellectual exercises with real impact. The Copenhagen meeting may be a bust, but countries from the United States to China are individually considering cap-and-trade schemes, carbon taxes, and other policies aimed at curtailing greenhouse gases. To be effective, a tax or cap-and-trade charge would have to force today’s emitters to pay the true "social cost of carbon"—in other words, the amount of damage a ton of carbon will cause in the coming centuries. Figuring out what that cost is, however, is no simple task. That’s largely because most of the bill won’t come due for many decades. A ton of carbon dioxide emitted today will linger in the air for anywhere from one to five centuries. Virtually every cost study shows that, even if economic growth continues apace (快速地) and there’s no effort to slash emissions, the damage from climate change will be negligible until at least 2075. It could take 100 years before we see noticeably negative effects, and even more before we need to launch massive construction projects to mitigate (减轻) the damage. What can we learn from the first paragraph
△ABC中，∠A:∠B:∠C=3:2:7，如果从AB上的一点D做射线l，交AC或BC边于点E，使∠ADE=60°，且l分△ABC所成两部分图形的面积相等，那么（）。
△ABC中，AB=5，AC=3，∠A=x，该三角形BC边上的中线长是x的函数y=f(x)，则当x在(0，π)中变化时，函数f(x)的取值的范围是（）。
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