The sum of products rule is an essential rule in calculus that provides a formula for finding the derivative of a product of two functions. It states that the derivative of the product of two differentiable functions f(x) and g(x) is equal to the sum of the product of the derivative of f(x) with g(x) and the product of f(x) with the derivative of g(x), i.e., d/dx(f(x)g(x)) = f'(x)g(x) + f(x)g'(x). This rule is crucial for differentiating complex functions and finds widespread application in various branches of science and engineering.
