first law of the mean for integrals

first law of the mean for integrals

[¦fərst ¦lȯ əvthə ¦mēn fȯr ′int·ə·grəlz]
(mathematics)
The proposition that the definite integral of a continuous function over an interval equals the length of the interval multiplied by the value of the function at some point in the interval.