已知抛物线y=2x2+1。求 （1）抛物线上哪一点的切线的倾斜角为45°？ （2 发布时间：2017-05-12 10:47 │ 来源：www.tikuol.com 题型：解答题 问题： 已知抛物线y=2x2+1。求（1）抛物线上哪一点的切线的倾斜角为45°？（2）抛物线上哪一点的切线平行于直线4x-y-2=0？ （3）抛物线上哪一点的切线垂直于直线x+8y-3=0？
题型：解答题 阅读理解。 A new supermarket put on a notice inside the entrance. It said, "Remember, once a week, one of our customers (顾客) gets free goods (things that cost nothing). This may be your lucky day!" All thehousewives who went to the supermarket had one great hope: to be the lucky customer who didn't haveto pay for her shopping. For several weeks Mrs Blake hoped to be the lucky customer. Unlike many other customers, she never gave up hope. Her kitchen was full of things she did not need. She dreamed of the day, when the manager of the supermarket would come and say to her, "Madam, this is your lucky day and everythingin your basket is free." One Friday morning, after she finished her shopping and had taken all the things to her car, she found that she had forgotten to buy tea. She went to the supermarket, got the tea and went towards the check-out. As she did so, she saw the manager of the supermarket come to her. "Madam," he said, "congratulations! You are our lucky customer and everything in your basket is free!" 1. From the notice in the new supermarket, we know that ______. [ ]A. customers could buy things at lower prices once a week B. the customer who bought the least goods didn't have to pay C. just one customer could get free goods once a week D. the first customer who bought goods in the supermarket was the lucky one 2. What was Mrs Blake's hope? [ ]A. To buy something cheaper in the supermarket. B. To see the manager of the supermarket. C. To buy everything she needed in the supermarket. D. To be the lucky customer. 3. Why did Mrs. Blake go back to the market after her shopping? [ ]A. Because she wanted to see who would be the lucky customer.B. Because she forgot to buy one more thing. C. Because she had to pay for her shopping. D. Because she wanted to get another chance to be the lucky customer. 4. Which of the following is NOT TRUE according to the passage? [ ]A. The manager of the market was a clever businessman. B. In fact the notice for free goods was a trick (诡计).C. Mrs. Blake's dream came true at last. D. Mrs. Blake did shopping every week in the past several weeks. 5. What would Mrs. Blake probably say when she heard the manager's words? [ ]A. "Oh, my God!" B. "How lucky I am!" C. "Everyone has a lucky day." D. "It's very kind of you!" 查看答案
题型：解答题 某研究者为了验证氯霉素对伤寒的疗效，在408例伤寒患者中进行对照实验，其中251例用氯霉素治疗，其余157例不用。结果使用组251人中死亡20人，病死率7．07％；未用组157人中死亡36人，病死率22．8％。下面说法错误的是（）。A.人体实验在临床医学中的价值和道德意义是无可非议的B.无道德代价的实验，在医学科学方面并非都能做到C.在临床医学研究中，使用安慰剂是心理实验，但要付出道德代价D.无道德代价的实验，在医学科学方面是可以完全做到的E.安慰剂虽没有药物作用，但确有一定的效果 查看答案