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

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result after division and put it in two places; with this
and the complement of the elongation divided by 15, using
Samkramagaṇita, we have successively Vibhā and Swabhā''.
Comm. Here, the meaning of taking the complement
of the elongation and dividing by 15 is to obtain the
magnitude of MD directly; for, (90 - e) / 15 = 6 - e/15 =
MG - e/15 = MG - GD = MD where e is the elongation
and e/15 is the Sukla. In other words, finding the Sukla
by dividing the elongation by 15 and subtracting it from
the radius to get MD is the same as taking the complement
of the elongation and dividing it by 15 to obtain MD.
Bhāskara quotes in the course of the commentary,
the verse from his Leelāvatī, namely "भुजाद्वर्गितात् कोटिकर्णान्त
राप्तम् द्विधा कोटिकर्णान्तरेणोनयुक्तम्। तदर्धे क्रमात्कोटिकर्णौ भवेताम्,
इदं धीमताऽऽवेद्य सर्वत्र योज्यम्" which means B² / (K - k) = K + k
since K² - k² = B². This situation arises when the Bhuja
B and the difference of Koti and Karṇa ie. K - k are given
and it is required to find K and k separately.
Verses (8) and (9). Draw a circle with radius 6
angulas to represent the disc of the Moon. Mark the disc
with the Cardinal points signifying the east, west, north
and south. Compute the Valana as directed in verse (5)
(which represents E' G' in fig. 119) and mark it off as a
Hsine from the west point w in the last quarter and from
the east point e in the first quarter. From the centre M
of the Moon's disc, mark off Vibhā MC (computed as
directed) along the join of MG'. With centre C and
radius Swabhā (already computed as directed) draw a circle.
The spherical sector of the Moon's globe thus demarked by
the arc of the circle ADB namely AGBD is found to have
the elevated cusp in the opposite direction in which
the Valana has been marked.