I have to do this question in my assignment...
I studied frobenius group from Permutation groups by Dixon and this is the given definition in it for Frobenius group so I guess I have to assume this definition which is in Rotman that a group is frobenius iff it contains a proper subgroup $H \neq 1$ s.t. $H \cap gHg^{-1}=1$ for all $g \notin H$. How should I proceed now.