7.04与6.95保留一位小数的近似数都是7.0.______.(判断对错)
7.04≈7.0(保留一位小数),
6.95≈7.0(保留一位小数),
故答案为:√.
已知f0(x)=x•ex,f1(x)=f′0(x),f2(x)=f′1(x),…,fn(x)=f′n-1(x)(n∈N*).
(Ⅰ)请写出fn(x)的表达式(不需证明);
(Ⅱ)设fn(x)的极小值点为Pn(xn,yn),求yn;
(Ⅲ)设gn(x)=-x2-2(n+1)x-8n+8,gn(x)的最大值为a,fn(x)的最小值为b,试求a-b的最小值.
根据短文内容和首字母提示,在下文空格处填入适当的词使短文完整。(每空一词)
Everyone knows that exercise is important. We all need to exercise. Doctors say i _小题1:____ is good for us. It makes your heart and body s__小题2:___. Children who often exercise are more alert(灵活的). This means they do better in tests and schoolwork than those who don’t exercise.
There are many w__小题3:____ to exercise. You can walk, run, swim, skate, or play ball games. Make sure you e__小题4:___ in the following ways: you have to like what you’re doing. Exercise enough --- but not too m__小题5:____. It’s best to exercise t__小题6:___ each week. Thirty minutes each time is enough. Try all kinds of things until you find one, two or even three sports that feel r__小题7:__for you.
You can exercise at fitness centers (健身中心). They have l__小题8:____ of equipment (设备) there . The equipment will help exercise your arms, legs and other parts of your body to make you f __小题9:____. Some people buy equipment for their homes. But it is very expensive.
Exercising can be fun. Friends can exercise t _小题10:____ at a fitness center, or they can play sports together. How do you exercise?