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

423 rendered a Kōti and is placed along V ☉, So the quantity √(H sin² Z☉ - H sin² ZV) which is the Kōti of the △ formed by H sin Z☉ and H sin ZV, corresponds to the Kōti of Sphuta-lambana ☉D. So we call √(H sin² Z☉ - H sin² ZV) as Dṛk-nati, in as much as the Sphutalambana being placed along V☉ in the form of a Karṇa when V☉ is Dṛk-mandala-nata, continues to be placed along V☉ in the deflected position also and becomes a Kōti corresponding to the Kōti of the triangle formed by H sin Z☉ and H sin ZV ie. corresponding to the quantity √(H sin² Z☉ - H sin² ZV). The Sphuta- lambana should be construed as being associated with Dṛk-mandala-nata which term is now abbreviated to the term Dṛk-nati. At A of fig. 92, the Dṛk-nati = √(R² - H sin² ZV) = H cos ZV = H cos ZV = Vitribha-lagna-Śanku. Hence the proportion proceeds in accordance with this Dṛk-nati. Verse 6 (latter half) and first half of verse 7. Alternative method of obtaining parallax in longitude. √(((H cos ZV) / (R/4))² - ((H cos Z☉) / (R/4))²) or √(((H sin Z☉) / (R/4))² - ((H sin ZV) / (R/4))²) gives the parallax in longitude expressed in nādīs. Comm. These formulae just constitude another mode of expressing the parallax in longitude and the equivalence of the formulae with the formula (4/R) Dṛk-nati is evident. Latter half of verse 7. Use of the parallax in longitude. The time of the ending moment of New Moon ie. the moment of geocentric conjunction is to be rectified by this