History of Hindu Mathematics: A Source Book v2.c17.s8.50

v2.c17.s8.50

An application of this rule is found in Śrīdhara’s *Triśatikā*, in connection with finding the number of terms of an A.P.⁴ *i.e.*, n = (√(8bs + (2a - b)²) - 2a + b)/2b, where a is the first term, b the common difference and s the sum of n terms.