规律性问题是初中阶段的一类常见题型,对于学生来说,解决起来存在一定的难度.针对此类问题,也没有绝对统一的方法去解决,主要依靠学生细心观察,寻找其中的规律.简单一些的规律,学生找起来还不太困难,但是对于关系复杂一些的问题就很不容易解决了.对于复杂些的规律问题,其中有一部分,就是通项公式与序号有直接关系的,我们可以用二次函数法来解决.例1如图1,观察图形,则第n个图形中三角形的个数是() Regularity is a common type of junior high school stage, for students, there are some difficulties to solve.For these problems, there is no absolute uniform method to solve, mainly rely on careful observation of students to find the laws. Simple rules, students find it is not too difficult to find, but for the complex relationship between the problem is not easy to solve.For the complexity of the law, some of which is the general formula and serial number has a direct relationship, we Can be used to solve the quadratic function Example 1 Figure 1, observe the graph, the number of triangles in the nth graph is ()