If the directional derivative of the function at the point is zero in the direction , then has a local minimum or local maximum at .

The distance is symmetrical, that is .

The divergence of is

The line integral of the vector field along the curve is

The function has a maximum at , if for any .

The function is continuous at if and only if all its coordinate functions are continuous at .

The distance is

The probability density function of the exponential distribution is

• , if
• , if

Let be a 3-dimensional bounded region and its boundary the surface . If is a continuously differentiable vector field, then

If the vector field where has a potential function if and only if for any one has