Jiangxi Jiangsu

First of all, Jiangxi is a big competition province, and the average level of mathematics is second to none in the country. Therefore, the topic of this province has always been known as difficult to think and difficult to calculate. Please refer to its titles in 2008 and 2009 for details. Doing all the suggestions carefully will give you fresh gains.

Then talk about the hot Jiangsu roll this year. Why did you put him here? It is not because its topic is so difficult and unreasonable, but that such a set of questions is only suitable for pre-test training, not for college entrance examination. Why do you say that? First of all, there are many topics in this set of papers, especially the second topic in the last volume, which can give people a nervous feeling. Then, the topic is too messy, the difficulty connection is inappropriate, and the 23 questions are not as difficult as expected, so they should not be put at the end.

The first problem is obviously to use cosine theorem, and then point out the closure of rational number multiplication and division operation; The second question is more natural, because if we want to generalize it to nA, there are two ways of thinking: 1 is a rising power. First, take it to 2kA to prove that nA is a rational number when n is even, and then use the sum angle formula to prove that the conclusion is also valid when n is odd. Then this place obviously applies to induction; 2 is to think of induction directly. What needs to be mentioned here is that the former method came to my mind first, but because I think sine is needed and it is not easy to change there, I naturally went to the second method.

The above is the train of thought analysis of 23 questions, please advise.

Finally, we can find a trend from the topic of 10, that is, induction, reduction to absurdity, elementary number theory and deductive reasoning. Some common methods of higher mathematics gradually gained the upper hand, while the problems of similar functions and derivatives that were flooded for a while gradually retreated. This trend is certain. After all, our knowledge of derivatives and integrals is far from enough to solve profound function problems.

I hope the above contents are helpful to you.