The proofs of 1 and number two are generally mean value theorems, and most of them are Lagrangian. Generally, several matching skills of several original functions with parameters can be summarized. 13 take an examination of Lagrange, and the second question was saved by Lagrange twice in a row. There are also test sites combining inequality and mean value theorem, which require a little higher.

2. The big problem of linear algebra has quadratic form, and the eigenvalue is tested when it is linked to the solution. Generally, the big questions of high numbers are tested every year, but the double integral is generally an examination of physical application; There is also a proof problem, the complex calculation of multivariate partial derivatives; A conditional extreme value; There is also a big problem of one-dimensional integration; There is also a differential equation, but it is also an application problem, which is linked to physical knowledge. You should be patient with this topic.

Basically, this is all the big questions about the number 2. I hope these can help you. I also took the 14 postgraduate entrance examination. Come on! If useful, please adopt it in time, thank you!