Slope vs elasticity of demand function - Is it the same thing? Do the slope of a linear demand function and the elastisicy of demand coincide when we use specific preferences for pricing. As a paradigm, if we consider the case of CARA normal preferences, by solving the proble of the represenative conumer, we know that the demand function is a linear one. In this case the slope and the elasticity of the demand function coincide, but is this the case in general?
No, slope of a demand function is $\frac{\partial q(p)}{\partial p}$ elasticity of demand is $\frac{\partial q(p)}{\partial p} \frac{p}{q(p)}$. So they cannot be same except in some special cases.