The document discusses the cost of capital and how it is calculated for different sources of financing. It defines cost of capital as the minimum rate of return a firm requires to undertake an investment. It then provides formulas to calculate the cost of various sources including debt, preferred shares, common equity, and retained earnings. It also discusses weighted average cost of capital (WACC), which is a weighted average of the costs of each source of financing used by a company. An example is provided to demonstrate how to calculate WACC.