Solve Best Fit Curve with Least Squared Method

This function will solve a best fit curve for the given data and equation by user using least squared method.

This function will solve a best fit curve for the given data and equation by user using least squared method. Please input the equation number and if you want to see the best fit curve of the equation press '1'. You can input 'x' & 'y' column vector or from an excel file where 'x' & 'y' is in two columns. For this, don't put any input when calling the function, only call the function like: y=curve_fitting. Then input file name like: curve_data.