calculation of operating profit From the end of the 19th century to the early 20th century, car designers focused their energies on the development and innovation of mechanical engineering. First half of the 20th century, all about the basic structure of the car has been invented, automotive designers begin from the outside to improve on modelling, and successively introduced the aerodynamics, fluid mechanics, human body engineering and industrial modelling design (industrial aesthetics), etc His European central bank held interest rates unchanged and signaled that it would maintain its aggressive currency, despite data showing strong economic performance in the region. The new classic "perfect" price mechanism Point 3: look at the process. The trust process of p2p platform is not strict, including the borrower's identity review, professional evaluation investigation, comprehensive audit risk, mortgage notarization, etc. Ms lagarde said she recently to Britain and the European Union in the civil rights, Northern Ireland and financial settlement negotiations welcome Famous British economist hicks and others argue that the above theory did not consider the factor of income, and therefore unable to determine the level of interest rates, in 1937, and puts forward the is-lm model on the basis of general equilibrium theory. It establishes a theory of interest rates and income at the same time that the four factors of savings and investment, money supply and monetary demand interact.