Surya Siddhanta
राशिलिप्ताष्टमो भागः प्रथमम् ज्यार्धम् उच्यते । तत् तद्विभक्तलब्धोनमिश्रितम् तद् द्वितीयकम् ॥
The eighth part of the number minutes contained in a sign (i. e. 1800) is the first sine. Divide the first sine by itself, subtract the quotient from that sine, and add the remainder to that sine: the sum will be the second sine.
english translation
rAziliptASTamo bhAgaH prathamam jyArdham ucyate । tat tadvibhaktalabdhonamizritam tad dvitIyakam ॥
hk transliteration by Sanscript