题干

函数y=sin2x的图象的一个对称中心为(  )

A:(0,0)

B:(π4,0)

C:(π412

D:(π2,1)

上一题 下一题 0.0难度 选择题 更新时间:2020-03-06 03:56:55

答案(点此获取答案解析)

C

同类题3

阅读理解

    Some people will do just about anything to save money. And I am one of them. Take my family's last vacation. It was my six-year-old son's winter break form school, and we were heading home from Fort Lauderdale after a week-long trip. The flight was overbooked, and Delta, the airline, offered us $400 per person in credits to give up our seats and leave the next day. I had meetings in New York, so I had to get back. But that didn't mean my husband and my son couldn't stay. I took my nine-month-old and took off for home.

    The next day, my husband and son were offered more credits to take an even later flight. Yes, I encouraged—okay, ordered—them to wait it out at the airport, to "earn" more Delta Dollars. Our total take: $1,600. Not bad, huh?

    Now some people may think I'm a bad mother and not such a great wife either. But as a big-time bargain hunter, I know the value of a dollar. And these days, a good deal is something few of us can afford to pass up.

    I've made a living looking for the best deals and exposing (揭露) the worst tricks. I have been the consumer reporter of NBC's Today show for over a decade. I have written a couple of books including one titled Tricks of the Trade: A Consumer Survival Guide. And I really do what I believe in.

    I tell you this because there is no shame in getting your money's worth. I'm also tightfisted when it comes to shoes, clothes for my children, and expensive restaurants. But I wouldn't hesitate to spend on a good haircut. It keeps its shape longer, and it's the first thing people notice. And I will also spend on a classic piece of furniture. Quality lasts.