Harmonic functions, defined as twice continuously differentiable functions satisfying Laplace’s equation, have long been a subject of intense study in both pure and applied mathematics. Their ...

A partial differential equation (PDE) is a mathematical equation that involves multiple independent variables, an unknown function that is dependent on those variables, and partial derivatives of the ...

Partial derivatives of production functions are necessary in many instances to characterize the technology of firms. We present here a general method to recover the first derivatives of the production ...

We like mechanical calculators like slide rules, but we have to admit that we had not heard of the Ott Derivimeter that [Chris Staecker] shows us in a recent video. As the name implies, the ...