Counterexample Definition and 52 Threads

As a problem I was asked to show that phi, as defined by: \phi_n(t) = \frac{n}{\pi(1+n^2t^2)} Satisfies the property that for any f with the property to continuious at 0, then: \lim_{n\rightarrow\infty} \int_{-\infty}^{\infty} \phi_n(t)f(t)dt = f(0) But if we let f be 1/phi, we see that it...

Basically, I have to show an example such that for a nonabelian group G, with a,b elements of G, (a has order n, and b has order m), it is not necessarily the case that (ab)^mn= e. where e is the identity element. im not sure where to start. =\