was workin on a modigliani and miller problem where re=r0+(r0-rd)(1-tax)(d/e) and instead of using r0=100% equity financed company, the answer had r0=wacc, even though the company was not 100% equity financed.
Is the formula used to find the new cost of equity, given a change in debt, regardless of if r0=100% equity is used. Or does it only work when r0=100 Equity finance?