解析学, or "analysis," is a branch of mathematics that focuses on the study of limits, continuity, derivatives, and integrals. It provides the foundational tools for understanding functions and their behaviors, which are essential in various fields such as physics, engineering, and economics. The subject is often divided into two main areas: real analysis, which deals with real numbers and functions, and complex analysis, which focuses on complex numbers and their functions. Key concepts in 解析学 include the derivative, which measures how a function changes, and the integral, which represents the accumulation of quantities.