Questions: If a price-demand equation is solved for p, then price is expressed as p=g(x) and x becomes the independent variable. In this case, it can be shown that the elasticity of demand is given by E(x)=-g(x)/(x g'(x)). Use the given price-demand equation to find the values of x for which demand is elastic and for which demand is inelastic.
p=g(x)=9000-0.1 x^2
The values of x for which the demand is elastic are
(Simplify your answer. Type your answer in interval notation. Type an exact answer, using radicals as needed. Use integers or fractions for any numbers in the expression.)
Transcript text: If a price-demand equation is solved for $p$, then price is expressed as $p=g(x)$ and $x$ becomes the independent variable. In this case, it can be shown that the elasticity of dernand is given by $E(x)=-\frac{g(x)}{x g^{\prime}(x)}$. Use the given price-demand equation to find the values of $x$ for which demand is elastic and for which demand is inelastic.
\[
p=g(x)=9000-0.1 x^{2}
\]
The values of x for which the demand is elastic are $\square$
(Simplify your answer. Type your answer in interval notation. Type an exact answer, using radicals as needed. Use integers or fractions for any numbers in the expression.)
Solution
Solution Steps
To determine the values of \( x \) for which the demand is elastic or inelastic, we need to calculate the elasticity of demand \( E(x) \) using the given price-demand equation \( p = g(x) = 9000 - 0.1x^2 \). First, find the derivative \( g'(x) \). Then, substitute \( g(x) \) and \( g'(x) \) into the elasticity formula \( E(x) = -\frac{g(x)}{x g'(x)} \). The demand is elastic when \( E(x) > 1 \) and inelastic when \( E(x) < 1 \). Solve the inequality to find the intervals for \( x \).
Step 1: Define the Price-Demand Function
The price-demand equation is given by:
\[
p = g(x) = 9000 - 0.1x^2
\]
Step 2: Calculate the Derivative
The derivative of \( g(x) \) with respect to \( x \) is:
\[
g'(x) = -0.2x
\]
Step 3: Determine the Elasticity of Demand
The elasticity of demand \( E(x) \) is defined as:
\[
E(x) = -\frac{g(x)}{x g'(x)} = -\frac{9000 - 0.1x^2}{x \cdot (-0.2x)} = \frac{5(9000 - 0.1x^2)}{x^2}
\]
Step 4: Solve for Elastic Demand
To find the values of \( x \) for which demand is elastic, we solve the inequality:
\[
E(x) > 1
\]
This leads to:
\[
x < 173.2051
\]
Step 5: Solve for Inelastic Demand
To find the values of \( x \) for which demand is inelastic, we solve the inequality:
\[
E(x) < 1
\]
This leads to:
\[
173.2051 < x
\]
Final Answer
The values of \( x \) for which demand is elastic are:
\[
\boxed{(0, 173.2051)}
\]
The values of \( x \) for which demand is inelastic are:
\[
\boxed{(173.2051, \infty)}
\]