A History of the Kerala School of Hindu Astronomy (in Perspective) c8.s4.9

c8.s4.9

'Placing the (sine and cosine) chords nearest to the arc whose sine and cosine chords are required, get the arc difference to be subtracted or added. For making the correction, 13,751 should be divided by twice the arc difference in minutes and the quotient is to be placed as the divisor. Divide the one, (say sine), by this (divisor) and add to or subtract from the other (i.e., cosine), according as the arc difference is to be added or subtracted. Double this (result) and do as before (i. e., divide by the divisor). Add or subtract the result (so obtained) to or from the first sine or cosine to get the desired sine or cosine chords'.³