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

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Iṣṭa Śaṅku / Iṣṭa Hṛti = cos φ = constant = Dinārdha Śaṅku / Hṛti
= Sama-Śaṅku / Taddhṛti = Unmaṇḍala Śaṅku / Kujyā (d) (23)
Again by virtue of the proportionality of
Iṣṭa Hṛti / Iṣṭāntyā = Hṛti / Antyā = Kujyā / Charajyā (e) (24)
We have Ishta-Śaṅku / Ishtāntyā = Dinārdha Śaṅku / Antyā
= Unmaṇḍala Śaṅku / Charajyā
∴ Iṣṭa Karṇa × Iṣṭāntyā = Dinārdha Karṇa × Antyā
= Unmaṇḍala Karṇa × Charajyā (f) (25)
∴ Dinārdha Karṇa = (Unmaṇḍala Karṇa × Charajyā) / Antyā
as stated in the verse.
Verse 43. (Unmaṇḍala Karṇa × Kṣitijyā) / Hṛti
= (Sama Vṛtta Karṇa × Taddhṛti) / Hṛti = Dinārdha Karṇa.
Comm. From (c) and (d) above Dinārdha Karṇa ×
Hṛti = Sama Karṇa × Taddhṛti = Unmaṇḍala Karṇa ×
Kujyā (g). Khitijyā is the same as Kujyā.
From this the statement follows :
Verse 44. The ancient Achāryas found the gnomonic
shadows when the Sun is on the meridian, prime-vertical
and the Kona-Vṛtta (ie, Vertical when the northern or
southern Hindu azimuths are 45°) by different methods.
I consider him to be the very Sun illuminating the lotus-
faces of aitronomers, if anybody could give a method to
find the shadow in any required direction, which holds
good in all cases universally.