Provide an Appropriate Response $\int _ { a } ^ { b } \mathrm { f } ( \mathrm { x } ) \mathrm { dx }$

Essay

Provide an appropriate response.
-A student claims that $\int _ { a } ^ { b } \mathrm { f } ( \mathrm { x } ) \mathrm { dx }$ always exists, as long as a and b are both positive. Refute this by giving an example of a function for which this is not true.