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

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Taking H cos δ M = R and H sin δm = δm
P₂c = (H cos E δm) / R This is at the end of E₁ P₂ i.e.
at the end of K; so to get the corresponding chord in
the deferent we do Karnānupāta so that the result is
(H cos E δm) / R × R / K = (H cos E δm) / K as given by Bhāskara.
We have cut short Bhāskara’s method of Bhōgyakhanda
Sphutīkaraṇa to make it clear to a modern student. Since
P₂c is small, passing on from the H sine to the arc is not
necessary, for, the H sine of a small arc is equal to the arc
itself.
Bhāskara’s argument, however, is as follows:— “If for
225, we have Bhōgya Khanda, what for δm?” The result
is (B × δm) / 225; Then B is rectified as follows:— “When the
H cosine E is equal to the radius, i.e. initially in the H sine
table, the Bhōgyakhanda is 225, then what is it for H cos E?”
The result is (H cos E × 225) / R which we have to substitute
for B. Then if this be at the end of K what is it at
the end of R?” The result is (H cos E × 225) / R × δm / 225 ×
R / K = (H cos E × δm) / K as given.
Before we proceed to explain ‘शेषं च वक्रा विपरीतशुद्धौ’,
we shall explain what Bhāskara pointed out as a mistake in
Lallācharya.
Verse 40. Let Mathematicians understand that what
formula was given by Lallācharya for Sīghragatiphala is
not correct. When the anomaly is 90° or 270°, the gati-
phala vanishes and there will be gatiphala at the points
where it ought to be Zero according to his formula.
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