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

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Hṛti = O₁A = OO₁ + OA
= Kujyā + H cos δ or
Dhujyā VI since OO₁ =
DO₄ = Kujyā. The line in
the Equatorial plane cor-
responding to Kujyā is
Charajyā which is equal to
R tan φ tan δ (13) so that
we can write Kujyā =
R sin δ tan φ = H sin δ tan φ
(13'). Also from VI
[Fig. 40]
Antyā = R + Charajyā
= R + R tan φ tan δ (14)
which gives us the duration
of half the day where R
gives 6 hrs and Charajyā
the increment in day due
to φ and δ.
[Fig. 40]
Verse 18. To obtain the
magnitudes of the various
chords or the elements of
the latitudinal triangles.
The elements or the sides of all these latitudinal
triangles are mutually derivable from similarity.
Comm. Easy.
Second half of Verse 18. The radius multiplied by
the Kotis or Bhujas and divided by the Karnas gives
H cos φ and H sin φ.
Comm. The seven triangles except the second, of the
eight latitudinal triangles are compared here with the
second. Remembering Bhujas are the sides of the
triangles opposite to φ and Kotis opposite to 90 − φ,