Formal Definition of the Riemann Integral

Overview


The Riemann Integral was one of the first and simplest integrals to be defined.

Definition


The integral
{% {\displaystyle \int }_a^b f(x)dx %}
is defined as the limit of the sum
{% {\displaystyle \int }_a^b f(x)dx = lim_{\Delta x \rightarrow 0} \sum_{i=1}^{n-1} f(x_i) (x_{i+1} - x_i) %}
where the interval {% [a,b] %} is split into subintervals as [{% x_1, x_2, ... , x_n %}] where {% x_1 = a %} and {% x_n = b %}