4.3 An elasticity coefficient is the ratio of the percentage change in the forecast variable (y) to the percentage change in the predictor variable (x). Mathematically, the elasticity is defined as (dy/dx) x (x/y). Consider the log-log model, log y= /3o + /31 log x + c.

Express y as a function of x and show that the coefficient

{31 is the elasticity coefficient