已知函数f(x)=ax^3+bx^2+cx+d（a,b,c,d∈R）的图像与x轴交于A,B,C三点.若点B的坐标为（2,0）,且函数f(x)在区间[-1,0]和[4,5]上有相同的单调性,在区间[0,2]和[4,5]上有相反的单调性.（1）求c的值；（2）求b

已知函数f(x)=ax^3+bx^2+cx+d（a,b,c,d∈R）的图像与x轴交于A,B,C三点.若点B的坐标为（2,0）,且函数f(x)在区间[-1,0]和[4,5]上有相同的单调性,在区间[0,2]和[4,5]上有相反的单调性.（1）求c的值；（2）求b
已知函数f(x)=ax^3+bx^2+cx+d（a,b,c,d∈R）的图像与x轴交于A,B,C三点.若点B的坐标为（2,0）,且函数f(x)在区间[-1,0]和[4,5]上有相同的单调性,在区间[0,2]和[4,5]上有相反的单调性.
（1）求c的值；
（2）求b/a的取值范围；
（3）求|AC|的最大值和最小值

已知函数f(x)=ax^3+bx^2+cx+d（a,b,c,d∈R）的图像与x轴交于A,B,C三点.若点B的坐标为（2,0）,且函数f(x)在区间[-1,0]和[4,5]上有相同的单调性,在区间[0,2]和[4,5]上有相反的单调性.（1）求c的值；（2）求b
(1)
对f(x)求导：
f'(x)=3ax^2+2bx+c
由题意f'(0)=0故c=0
(2)
f'(x)=x(3ax+2b),且[0,2]和[4,5]上有相反的单调性
故有2≤-2b/3a≤4
故-6≤b/a≤-3

Described some of the ideas above, pulled a number out of view, to think that the cut version is a waste station, I can only see some of the foresight of the scene, after all, there are a lot of good ...

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Described some of the ideas above, pulled a number out of view, to think that the cut version is a waste station, I can only see some of the foresight of the scene, after all, there are a lot of good conduct and the establishment of the central portal. I was very optimistic about the tendency to carry out the central portal, as a group owners, if there is no comparable good operational projects, no harm can think of the central portal. Farewell also some central portal can have more owners share some experiences and tips for aspiring webmasters to participate in the enemy to provide some pointers and suggestions.
5, conducive to developing contacts. Both Baidu, DZ or alibaba, hope we can pull out to do the central community, the central site, each group, message each institution represents his position and interests. But they often do activities at the central site as a central portal owners, participating in the process, naturally exposed to a lot of fierce character, not the body as a person, that is what the company's director. Even if these contacts for your business is temporarily unable to play for any assistance, but does not guarantee that these contacts will not benefit you in the future and interests. The success of a network of training organizations can only succeed, and this can also owners of other types of disadvantage can not be compared.
4, easy to make the brand and reputation. Have to confess, there is no lack some of the network traffic circle more and more groups of cash owners, there is a station group can also can be accumulated after a very long time due to many sites, there can be the type of site Nabuchushou Many webmasters and sites are not well known, little understood by the human circle for the owners. But on the central portal owners, this is somewhat different. Central portal to traffic is small, but relatively easy to make a brand and visibility. From the large terms of trade and the environment, from the central to the industry sectors for the central portal type web sites are recognized, and this gives a lot of other types of owners are jealous of reading, which is why so many owners in the central pro-Lai portal. After all,discount nike air max shoes, recognition of the current society is not enough for webmasters.
2, easy to build a high weight. Once the central portal to operate, no matter what kind of flow, weight certain high. Friends of administrative bodies at all levels of the site chain, the central portal of the Friends of the chain of various search engines like this site. Meanwhile, as the central portal of the owners, go find someone to do Friends of the chain of midnight, all came to be straighter spine, tone is higher. As what? Not waste the next station, but next door, though the center. After a day's accumulation of a higher weight content with the amount of tens of millions, traffic does not go up will not work. Many of the webmaster portal into heaven to fight a party beginning to entertain the idea.
Nowadays more and more groups involved in the central portal webmasters, and even some county-level portals beginning of wind and water, which of course is good and the bad,nike air max TN, and some do very well, some do like the cut version of waste stations. Why is everyone so keen to the central portal to it? What after all, the central portal of the attraction? I share some of my views on this, the lack of place, but please correct me a lot.
1, the contents of large span, a large traffic base. We look at the central portal of the column structure to know, big and small, no less than 200 of the. Local, central; international, international; current affairs, gossip; games, entertainment's. In short, any small part out alone, can make a very big part. In short, owners want is the effect of the way through the central portal alone, combined with the weight advantage of the central portal, be sure to span the breadth of content to achieve the ultimate. On the flow, it is clear that so many columns do not necessarily require that each part can be very out of color, but on the search engine is concerned, there can be hit. Strange about the central user is concerned,cheap nike air max, so much the content, we can satisfy your needs it. If you are not operated by the central portal, you go on so many columns, useful for the waste station can be determined. From this point of view, the central portal and the waste station only difference between a Title.
3, flow easily realized, business forms and easy changes. Since the high-traffic sites, but of course, would be surplus cash flow, advertising everywhere, pop, video ads are everything. After the initial establishment of the station so the liquid can be realized, the rapid accumulation of seed capital, if the chief operating without side bigger, so the right track, the team of the company operation, and can quickly stop the bleaching, the change to stop commercial . For example, to carry out the central forum to do mall, do buy, shop for the central do feature advertisements. Who can go to track your "original sin" ah.

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