High number formula: lim= 1-cosxtanx-sinx. Advanced mathematics generally refers to advanced mathematics (the name of basic subject). Broadly speaking, all mathematics except elementary mathematics is advanced mathematics, and some call algebra, geometry and simple set theory in middle school as intermediate mathematics, which is regarded as the transition between elementary mathematics in primary and secondary schools and advanced mathematics in universities.

Algebra is a branch of mathematics, which studies the general solutions and properties of numbers, quantities, relationships, structures and algebraic equations (groups). Elementary algebra is generally taught in middle schools, introducing the basic ideas of algebra: studying what happens when we add or multiply numbers, understanding the concept of variables and how to establish polynomials and find their roots. The research object of algebra is not only numbers, but various abstract structures. Among them, we only care about various relationships and their nature, but we don't care about the question "what is the number itself". The common types of algebraic structures are groups, rings, fields, modules, linear spaces and so on.