Forecasting the number of electricity customers is a crucial aspect of resource planning and management at PT PLN Tasikmalaya. One method that can be used to improve forecasting accuracy is Lagrange Interpolation, which constructs an interpolation polynomial based on known data points. Although this method has been widely applied in various fields, its use in forecasting the number of electricity customers remains rare. Therefore, this study aims to explore the application of the Lagrange Interpolation method in forecasting the monthly number of electricity customers at PT PLN Tasikmalaya.In this study, historical electricity customer data was used as the basis for constructing an interpolation polynomial, which was then utilized to forecast the number of customers from January 2024 to May 2024. The forecasting results indicate an increase in the number of electricity customers each month. After rounding, the estimated number of customers is 274,952 in January 2024, 278,142 in February 2024, 284,402 in March 2024, 296,031 in April 2024, and 316,391 in May 2024.The findings of this study demonstrate that the Lagrange Interpolation method can be applied to forecast the monthly number of electricity customers at PT PLN Tasikmalaya. However, to improve forecasting accuracy, it is recommended to compare this method with other forecasting techniques and consider external factors that may influence the number of customers, such as government policies, economic growth, and changes in electricity consumption patterns.

The solutions of limit problems is one of fundamental concepts in real analysis, applicable in various fields of mathematics and other sciences. However, determining limit can sometimes present challenges, particularly when the fuction in question is complex and difficult to solve manually. This study demostrates the use of MATLAB as a tool to assist in solving such problems numerically. The findings show that MATLAB is realible in calculating the limits of specific fuctions, offering accurate solutions more efficiently and quickly compared to manual methods.

This research aims to determine the role of good use of Indonesian in the learning process for students, especially in mathematics set material. Apart from that, this research also aims to reveal various theories that are relevant to the problem being researched, and is carried out by re-analyzing data that has been collected from other research results in order to prove the correctness of the data and its validity based on the title of the research. The scope of this research is to measure students' understanding using good Indonesian regarding understanding elements in mathematical set material. The research method used is quantitative research. From the research that has been carried out, it can be seen that every reference used in this research states that the use of Indonesian plays a very important role in the learning process for students.