ostensibly discontinuous antiderivative
The real function
(1) |
is continuous for any (the denominator is always positive) and therefore it has an antiderivative, defined for all . Using the universal trigonometric substitution
we obtain
whence
This result is not defined in the odd multiples of , and it seems that the function (1) does not have a continuous antiderivative.
However, one can check that the function
(2) |
is everywhere continuous and has as its derivative the function (1); one has
References
- 1 Ernst Lindelöf: Johdatus korkeampaan analyysiin. Fourth edition. Werner Söderström Osakeyhtiö, Porvoo ja Helsinki (1956).