Thanks for that moo, i thought it was somethign similiar..
the question also wants the mgf to be sketched when b=k=0.5 and to show the points t=0, t=0.2. I am a little bit confused, as to what the significance / point of drawing these points on the graph shows, and also the significance of the mgf graph? ie. i know about area under F(y) and f(y).. just wondering if there is a similiar significance for an mgf?