The expression g'(x) \cdot h(x) - g(x) \cdot h'(x) represents the derivative of the product of two functions, g(x) and h(x) , using the product rule in calculus. Here, g'(x) is the derivative of g(x) , and h'(x) is the derivative of h(x) . This formula helps in finding the rate of change of the product of two functions. This expression is also known as the Wronskian when used in the context of linear differential equations. It is useful in various applications, including physics and engineering, where understanding how two changing quantities interact is essential.