The right side of the equation can be regarded as the function F(r_i) of the independent variable r_i. Therefore, there is a definite functional relationship between d_i and r_i:
The right side of the equation can be seen as the independent variable R_ Function f of I (r_i). Therefore, D_ I and R_ There is a definite functional relationship between I:
The right side of the equation can be regarded as a function f (r_i) with the independent variable r _ i. Therefore, there is a definite functional relationship between d_i and r_i: