Recent content by josh146

I'm reposting this because there was a problem with the title/LaTeX last time. Homework Statement Solve the wave equation (1) on the region 0<x<2 subject to the boundary conditions (2) and the initial condition (3) by separation of variables.Homework Equations (1) \frac{\partial^2...

I'm pretty sure that f^{-1}(a) is used as shorthand for f^{-1}({a}). I'm still having trouble doing the question though. I'm sure it's simple but I'm not seeing how to define the set.

Sorry, I shouldn't have written 'inverse' in the title. For this map, f^{-1} is defined as the 'preimage' of the map.

Homework Statement Let H, K be subgroups of a finite group G. Consider the map, f : H \times K \rightarrow HK : (h,k)\rightarrow hk. Describe f^{-1}(hk) in terms of h, k and the elements of H\cap K. Homework Equations HK = \{hk : h \in H, k \in K \} f^{-1}(hk)=\{ (h',k') : f(h',k')=hk...