A white sheet of paper with handwritten notes on it, possibly from a student's notebook

A white sheet of paper with handwritten notes on it, possibly from a student's notebook. The writing is in black ink, mostly mathematical equations and formulas, with some Vietnamese text, likely related to solving mathematical problems. The writing is centered on the page, with more writing on the right side, and an empty section on the left. The paper is folded in the upper right corner, possibly to mark a place. The writing is clear and legible, with the numbers and symbols clearly distinguishable. The sheet of paper is the only subject in the image. The environment is a typical indoor setting, likely a classroom or a student's home, with a plain white background. The coordinates provided, 21.08 latitude and 105.817 longitude, correspond to a location in the city of Phú Thượng, Vietnam. The image likely depicts a piece of homework or study material related to mathematics, created by a student in the city of Phú Thượng, Vietnam.