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

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Comm. Equation (23) under verse 41 is
(Iṣṭa Śaṅku / Iṣṭa Hṛti) = (D.S. / Hṛti) = (S.S. / Taddhṛti) = (U.S. / Kujyā) = cos φ I
and 12 / K = (H cos z) / R (under verse 40)
ie. K = 12R / Iṣṭa Śaṅku which means
Dinārdha Karṇa = 12 R / D.S. ; Sama Karṇa = 12R / S.S.
and unmaṇḍala Karṇa = 12 R / U.S.
Substituting for the numerators in I
12R / (K × Iṣṭa Hṛti) = 12R / (DK × Hṛti) = 12R / (S.K × Taddhṛti)
= 12R / (U.K. × Kujyā) II
∴ Iṣṭa Karṇa × Iṣṭa Hṛti = S.K. × Taddhṛti
= U.K. Kujyā
∴ Iṣṭa Karṇa = (Uumaṇḍala Karṇa × Kujyā) / Iṣṭa Hṛti
= (Sama Karṇa × Taddhṛti) / Iṣṭa Hṛti = (Dinārdha Karṇa × Hṛti) / Iṣṭa Hṛti
Verse 63. Just a caution.
If in any context where the word ūna-yuta has been
used, the quantity to be subtracted exceeds the quantity
from which it is to be subtracted, it goes without saying
that subtraction should be reversely effected and in the
place of addition subsequently prescribed subtraction should
be done and Vice-versa.
Comm. Bhāskara gives three examples to illustrate
his point. In verse 54, while defining Sūtra (H sin 90 – h)
we are asked to subtract chara from unnata when δ > 0