The relationship between the limit of a function and a definite integral on a given integral is given by:
[tex] \int\limits^b_a {f(x)} \, dx = \lim_{n \to \infty} \Sigma_{n=1}^nf(x_i)\delta x,\ \ [a,\ b][/tex]
Given [tex] \lim_{n \to \infty} \frac{\cos x_i}{x_i} \delta x,\ \ [2\pi,\ 3\pi][/tex], the equivalent definite integral is:
[tex]\int\limits^{3\pi}_{2\pi} { \frac{\cos x}{x} } \, dx[/tex]
