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A general exponential demand function has the form q = Ae−bp (A and b nonzero constants). (a) Obtain a formula for the price elasticity E of demand at a unit price of p.

Verified Answer :

E = (p/q)(dq/dp) 

dq/dp = -bAe^(−bp) 
(p/q)(dq/dp) = [p/Ae^(−bp)] (-bAe^(−bp)) 
                    = -pb

Answer:

\(E = -pb\)

Step-by-step explanation:

The Elasticity(E) of demand at a unit price of p is given by:

\(E= (\frac{p}{q}) \cdot (\frac{dq}{dp})\)

As per the statement:

A general exponential demand function has the form :

\(q = Ae^{-bp}\)

where, A and b is non zero constants.

Using derivative formula:

\(\frac{d}{dx}(e^{-x})= -e^{-x}\)

First find the derivative of q with respect to p.

\(\frac{dq}{dp} = -Ab \cdot e^{-bp}\)

⇒\(\frac{dq}{dp} = -b \cdot Ae^{-bp}\)

Using \(q = Ae^{-bp}\)

⇒\(\frac{dq}{dp} = -bq\)

then;

\(E = \frac{p}{q} \cdot (-bq) = -pb\)

⇒\(E = -pb\)

Therefore, a formula for the price elasticity E of demand at a unit price of p is, \(E = -pb\)