The Derivative of the Sine and Cosine. A New Derivation Approach

Abstract

A new method is presented for finding the derivative of the sine and cosine using the discoveries of Leibniz in calculus between the years 1675 and 1677, namely the derivative of the product and the quotient of two functions as well as the chain rule, yet long before the discovery of the derivative of the sine by Roger Cotes in 1722 and Euler in 1748.