The first chapter is about solving triangles.

Remember the formulas of sine theorem and cosine theorem.

Make clear what problems use sine theorem and what problems use cosine theorem.

The second chapter is the preface.

Remember the general formula of arithmetic progression and geometric progression and the summation formula of the first n terms?

Will use Sn to find the general term formula, and simply understand the common methods of sequence summation, such as reverse order addition, dislocation subtraction and split term elimination.

The third chapter is inequality

To understand the essence of inequality, we must find the relationship of inequality from practical problems.

Can solve quadratic inequalities in one variable, especially the discriminant of roots △

The knowledge of linear equation is in compulsory 2, but it may not be in compulsory 2 when studying compulsory 5.

In this section of linear programming, we need to know some knowledge of straight lines (slope of straight lines, general equations of straight lines).

Finally, the mean inequality, which is the focus and difficulty of inequality.