Question: Consider a Modigliani-Miller world with no taxes. In this world, consider a firm which is expected to generate constant cash flows in perpetuity. For this firm VU = VL = D+S and ks = k0 + (D/S)(k0 - kd). Now, assume that suddenly, a corporate tax at a rate T is imposed on the firm. Nothing else changes (i.e. the value of debt of the firm and k stay the same). Show that ks does not change. That is, show ks(new) = k where ks(new) is the value of ks (the required return on equity) in a world with taxes.