सिद्धान्तशिरोमणि: गणिताध्याय (भास्कराचार्य - ग्रहगणित, मध्यमाधिकार व स्पष्टाधिकार सटीक)

139 their mathematics led to them to make the centre of the eccentric circle coincide with the Sun himself. On this basis alone it was given to Copernicus to formulate helio- centric theory, sponsored by a thought that the Heavenly Sun could not be deemed as a satellite of the ‘ Mundane ’ Earth. (Ref. fig. 9). The same figure 9 will also serve the pur- pose to obtain the Sīghraphala, only M₁ M₂ will be now on the right hand side of the Sīghrocchas A₁ A₂, for, the latter will be taken to be in advance of the mean planets Kakshā- Vrittīya Madhyagraha M₁ (i.e. mean planet of the deferent) and prati-Vrittīya Madhyagraha M₂ (i.e. mean planet of the eccentric). The points A₁ add A₂ are themselves called the Kaksha-Vrittīya Sīghrōccha and prati-Vrittīya Sīgh- rōccha respectively. As was shown in the case of the Mandaphala from the eccentric figure 9, M₂ N₂ = r/R H sin (Kendra) so that PN₁ = r/R H sin (Kendra) × R/K = r/K H sin (Kendra) = (Antyaphalajya × Sīghrakendrajyā) / Sīghrakarna . We shall take this for elucidation in the appropriate context. Verse 19. Three Rasis each of 30° constitute a quad- rant, and there are four quadrants in a circle which are res- pectively odd, even, odd and even. In the odd quadrants the Kendra covered is itself called Bhuja whereas in the even ones, the complement thereof is called Bhuja. Also, the complement of the Bhuja is called the Koti. Verse 20. R − H sine = Co. H versine and R − H cosine = H versine and R − Co. H versine = H sine, R − H versine = H cosine. Verse 21. Also √(R² − H sine²) = H cosine, √(R² − H cosine²) = H sine. Similarly √(R² − Krantijya²) = Dyujya, √(R² − Dyujya²) = Krāntijya; √(R² − Drig-jyā²)