Taylor series
The earliest known examples of the Taylor series are the work of Mādhava of Sañgamāgrama in India in the 1300s. Later Indian mathematicians wrote about his work with the trigonometric functions of sine, cosine, tangent, and arctangent. None of Mādhava's writings or records still exists today. Other mathematicians based their work on Mādhava's discoveries and worked more with these series until the 1500s.