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

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Anya, we could put Anya = A² - H sin² a. As a matter
of fact in verse 50, we are asked to take H sin² ~ A²,
as Bhāskara wanted that the second case also be included.
Thus putting Anya = A² - H sin² a, equation I becomes
K² (A² - H sin² a) - 2 AsRK = - (Adya) so that
K = Anya ± √(Anya² - Adya) as given.
Verse 52. The Bhuja is to be obtained through
Karṇāgra from the equation a = b + s (already proved)
and Rb / S = H sin a {ie. S = bR / H sin a as already proved}.
This H sin a will be the same in the case of obtaining
two values of K ie. two shadows one in the morning and
the other in the afternoon, (the only difference being that
they will be on alternate sides of the East-West line).
Verses 53 and 54. Obtaining the shadow when time
is given.
In the two previous examples the magnitude of the
shadow was obtained in a given direction ; now we shall
obtain the same when time is given. The word unnata
stands for the time that has elapsed after Sun-rise or that
which is the balance of the day time. The unnata sub-
tracted from half-the-day gives what is called Nata.
The H sine of the unnata minus Chara or increased
by the Chara according as the Sun's declination is north
or south, is called Sūtra ; this multiplied by the H cos δ
and divided by the radius, is called Kalā.
Comm. (Ref fig. 51) The time measured by the arc
MN, that is the time in between the moment when the Sun
S is on the horizon and the moment when he is at L is
called the unnata ie. the time measured after rising and
the time measured by the arc NQ ie. the time in between