(mathematics, physics, potential theory) The partial differential equation (∂²𝜑)/(∂x_1²)+(∂²𝜑)/(∂x_2²)+⋯+(∂²𝜑)/(∂x_n²)=0, commonly written 𝛥𝜑=0 or ∇²𝜑=0, where 𝛥(=∇²) is the Laplace operator and 𝜑 is a scalar function.

The heuristic formula B=f(P,E), stating that behavior is a function of the person and their environment.

Any error common to all the observations of some individual; any tendency to error or prejudice due to the personal characteristics of some person for which allowance must be made.

plural of personal equation

(reaction kinetics) an equation expressing how the rate of a reaction depends on the concentrations of the reactants

The discrepancy between two kinds of solar time: the apparent solar time, which directly tracks the motion of the Sun, and mean solar time, which tracks a theoretical "mean" Sun with noons 24 hours apart.

plural of polar equation

plural of quadratic equation

plural of Airy equation

plural of algebraic equation