The function does not have a limit at if and only if all its coordinate functions do not have a limit at .

In the norm is defined as :

In an orthonormal system, the vectors are all pairwise orthogonal and have unit norms.

The triangle inequality is .

If is a linear transformation, then it has at least one eigenvector.

If for a random variable the expected value and the standard deviation exist, then for any positive number one has

The cumulative density function of the continuous uniform distribution is

• , is ,
• , if ,
• , is .

The characteristic distribution is the discrete probability distribution with possible values and probabilities

If is a random variable with values , … and the correspondent probabilities are , …, , then its expected value is

The standard deviation of the random variable is