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

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But PM is the H sine of m¹ where m¹ is called Sphuta-
kendra (m is called the madhya-Kendra). Hence
H sin m¹ = R/K × M₂N = R/K × Bhujajyā (in the eccentric)
∴ m¹ = H Sin⁻¹ (R/K × Bhujajyā) = PA₁
∴ M₁P = Sīghraphala = M₁ A₁ — PA₁ = Kakshya-
mandala Bahu minus the chāpa m¹ — Here a clear under-
standing of the word Bāhu or what is the same Bhuja should
be had. The arc pertaining to the angle m in the eccentric
is known as the Bāhu in the eccentric and that to the
angle m in the deferent as the Bāhu in the deferent. When
0<m<90, m is itself spoken of as Bāhu; when 90<m<180,
180—m is spoken of as the Bāhu; when 180<m<270,
m — 180 is the Bāhu and when 270<m<360, 360—m is
the Bāhu. Thus the Bāhu is that angle whose H sine will
be H sin m numerically. When it is said in the verse
‘त्रिज्याहता कर्णहृता भुजज्या’ the word Bhuja is the arc M₂A₂ as is
mentioned in the same verse ‘ज्ञेयोऽत्र बाहुः प्रतिमण्डलस्य’. The
second part of the verse divides the eccentric circle into
such quadrants that in them S'īghraphala increases from
Zero to a maximum, decreases again from a maximum to
zero, again increases from zero to a maximum and again
decreases from a maximum to zero. Thus at A₂ of the
eccentric the S'īghraphala is zero; at a₁, it is a maximum
namely the arc b₁c₁ where H sin b₁c₁ = a₁c₁ = r; Thus in
the course of A₂a₁ the arc of the eccentric the S'īghraphala
gradually increases from zero to a maximum and in the
course of a₁a₂ the S'īghraphala decreases from a max to zero.
Again from a₂ to a₃ it increases from zero to a max and
from a₃ to A₂ it decreases from the maximum to zero. Thus
the quadrants in the case of S'īghrapbala are not of 90° but
arcs A₂a₁, a₁a₂, a₂a₃ and a₃A₂ which are respectively of mag-
nitude 90° + H Sin⁻¹r, 90 — H Sin⁻¹r, 90 — H Sin⁻¹r and
90+H Sin⁻¹r. In the case of Mandaphala also, the quadrants
should have been of the same magnitude if the so-called
Karnānupāta has been postulated i.e. reducing the Manda-