CAPM approach for estimating the component cost of equity

. Under what situations would you want to use the CAPM approach for estimating the component cost of equity? The constant-growth model? (LG11-3)

Could you calculate the component cost of equity for a stock with nonconstant expected growth rates in dividends if you didn’t have the information necessary to compute the component cost using the CAPM? Why or why not? (LG11-3)

Suppose your firm wanted to expand into a new line of business quickly, and that management anticipated that the new line of business would constitute over 80 percent of your firm’s operations within three years. If the expansion was going to be financed partially with debt, would it still make sense to use the firm’s existing cost of debt, or should you compute a new rate of return for debt based on the new line of business? (LG11-5)