Question

what is improper integral???

Answer 1

http://www.youtube.com/watch?v=85-HNJyuyrU

Answer 2

could be an integral over an infinite path, like
\[\int_1^{\infty}\frac{dx}{x^3}\]

Answer 3

or it could be an integral that includes a point where the function is not defined, such as
\[\int_{-1}^1\frac{dx}{\sqrt[3]{x}}\]