1. The problem asks for a brief introduction to the Indian mathematician Bhaskar I and his notable contributions. 2. Bhaskar I, also known as Bhaskara I, was an Indian mathematician and astronomer who lived in the 7th century. 3. He is known for his works on arithmetic, algebra, and trigonometry. 4. One of his notable contributions was writing extensive commentaries on the works of Aryabhata, an earlier Indian mathematician. 5. Bhaskar I is credited with the earliest known use of the sine function in trigonometry. 6. He provided accurate approximations for sine values and methods to compute them. 7. His works helped in the development of Indian astronomy and influenced later mathematicians. Final answer: Bhaskar I was a pioneering Indian mathematician of the 7th century noted for advancing the study of trigonometry through sine function approximations and commentaries on Aryabhata's works.