纵观近年各地高考、模考数学中导数类型的压轴题,“多变元问题”是逐渐成为考查的热点题型,主要以双变元为主的“二元函数”、“二元方程”、“二元不等式”为代表在各类数学考试中屡见不鲜。这类问题中的变元个数有多个,在无法消元的情况下,只能通过变形化归实现求解,这类题型难度颇大,需要学生具备良好的转化与化归能力、代数变形能力,只有基本功扎实、方法运用娴熟,方能在这类 Throughout the recent years, college entrance examination around the country, the model of mathematics in the derivative of the type of finale, “multivariate problem ” is gradually becoming a hot test exam type, mainly based on the bivariate element of the “binary function ”Binary equation “, ”binary inequality " as the representative in the various types of mathematics exams are commonplace. There are many variables in this kind of problem. If they can not be eliminated, they can only be solved through transformation. These kinds of questions are quite difficult and require students to have good ability of transformation and transformation. Algebra Deformation ability, only the basic skills solid, skilled use of methods, can only be in this category