1) The topic is very difficult: 2 1 The first question of mathematical agriculture is the comparison between an infinitesimal and three roots. The form is scary, or the examinee's basic knowledge is not in place. In fact, this is a standard questions type with a regular infinitesimal ratio. This type of question has appeared twice over the years, but what can't be done is that this type of question has not been mastered.

2) Large amount of calculation: The real problem of 2 1 year needs more skills and properties, such as the eigenvalue and eigenvector of the sixth problem. If you write down the answers second by second, you won't remember them and won't be deduced because you are nervous in the examination room. This kind of question was passed in 70 1 year, and in 17 year.