Fitting Functions By The Nonlinear Least Square Method Being Applied In The Economic Development

In this thesis.I have introduced the way to solve the relationship between the GDP(GNP)measured by the PPP per person and the GDP(GNP)measured by the exchange rate per person in the same nation.And use the function to show this relationship with the theory of fitting functions by the nonlinear least square method.At the last,I introduce how to use this method to forecast the exchange rate of a nation.And as an example.I forecast the exchange rate of China.