Aga, Tole. “Finding the Values of Trigonometric Function Without the Use of Scientific Calculators: The Case of Tangent Function”. Ethiopian Journal of Science and Sustainable Development 11, no. 1 (January 22, 2024): 16-21. Accessed May 8, 2024. https://ejssd.astu.edu.et/index.php/EJSSD/article/view/413.