What is a characteristic of differentiable functions in relation to integration?

Differentiable functions exhibit a property known as the Leibniz rule or differentiation under the integral sign, which allows one to interchange differentiation and integration under certain conditions. This means that if you have a function that is differentiable with respect to a variable and that function is integrated over a certain range, you can take the derivative of the integral with respect to that variable, and it will yield the same result as differentiating the integrand first and then integrating.

This property is particularly useful in various applications, including solving complex integrals, where differentiating under the integral sign simplifies the process. It allows for a versatile approach when dealing with parameters in integrals, thereby showcasing the close relationship between differentiation and integration for a wide variety of functions.

The other options do not accurately characterize differentiable functions in relation to integration. For instance, differentiable functions can indeed be integrated, and they do not inherently yield only positive results. Additionally, a function being differentiable does not restrict it to just one integral form; many functions can be expressed in different ways through integrals.