What are the key principles and components involved in the preparation and analysis of a profit and loss ( P&L) account and how does it differ from other financial statements such as the balance sheet and cash flow statement? Can you provide examples of the types of revenues and expenses that are reported on a P\&L account, such as cost of goods sold, operating expenses and taxes, and explain the impact that these elements have on a company's overall financial performance? Additionally, what are some of the best practices and tools for analyzing and interpreting a P\&L account, such as profitability ratios and trend analysis, and how can companies use this information to make informed business decisions and improve their financial performance? Furthermore, how does a P\&L account reflect a company's operational efficiency and effectiveness, and how does it impact the decision of investors, credit providers and management