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.瓷器 | .丝绸 | .茶叶 | .中草药 |
国家主席习近平将于2015年5月8日至10日出席在莫斯科举行的纪念卫国战争胜利70周年庆典并访问俄罗斯。中俄双方将签署能源、航天、税务、金融、投资等领域合作文件。据此回答(1)~(3)题。
Nowadays, cell phones are part of our lives. Many people have cell phones. They can help us easily find people anywhere at any time. However, using cell phones too often may cause cancer(癌症). It’s reported that people who use a cell phone for 10 years or more may get brain cancer.
The suggestions below may help you reduce(减少) the risk of cancer:
When using your cell phone, try to keep it away from your body as much as possible. Don’t put it on the bedside table when you go to sleep.
When you’re on the cell phone, use the speaker(扬声器). In this way, you have just 1/100th of the contact(接触) with radiation you have when you hold it to your ear. An earphone is also a good idea.
Try to keep your conversations short. If you need to talk longer, use an ordinary phone instead.
Change ears when you’re using your cell phone. Before putting it to your ear, wait until the person you are calling picks up the phone.
Your phone gives out radiation when you talk or send messages, but not when you’re listening or getting messages. Listening more and talking less can lower the risk of cancer.
Do not use your cell phone when the signal(信号) is weak or when moving at a high speed, for example in a car or on a train. At high speeds your phone is trying to pick up signals, and this increases the radiation it gives out.
已知是等差数列,是等差数列,且,,,.
(Ⅰ)求的通项公式;
(Ⅱ)设,求数列的前项和.
抛物线平移后的位置如图所示,点A,B坐标分别为、,设平移后的抛物线与y轴交于点C,其顶点为D.
求平移后的抛物线的解析式和点D的坐标;
和是否相等?请证明你的结论;
点在平移后的抛物线的对称轴上,且与相似,求点的坐标.