[math]f(x) = tan^{-1}(x)[/math]
The inverse of this function is:
[math]x = tan^{-1}(f(x))[/math]
[math]f(x) = tan(x); -\frac{\pi}{2} < x < \frac{\pi}{2} [/math]
The domain is restricted on the inverse because [math] f(x) = tan^{-1}(x) [/math] is restricted to the range [math]-\frac{\pi}{2} < f(x) < \frac{\pi}{2}[/math]. Thus the function [math]f(x) = tan^{-1}(x)[/math] is continuous on the domain of all real numbers, but its inverse is not.
*edit*
This is the case for every function whose domain is all the real numbers, but whose range is restricted due to a horizontal asymptote or an absolute minimum. The inverse will not be continuous on the domain of all real numbers. Perhaps an even better example would be the function [math]f(x) = x^{2}[/math], whose inverse, [math]f(x) = \sqrt{x}[/math] is not only not defined for x < 0, but isnt a function at all, by the vertical line test.