If the cost of debt is generally below cost of equity, why would firms want to issue equity?

Question 3: If the cost of debt is generally below cost of equity, why would firms want to issue equity?

Question 4: How reliable are ratios when used to evaluate fast-growing companies? How is it used to evaluate fast-evolving economic sectors such as Internet companies? How are ratios helpful in evaluating turnarounds? What is the best measure of performance for companies in cyclical sectors?