Indifference Curve
1. Stating the problem: We need to graph a typical indifference curve for a utility function. An indifference curve shows combinations of goods that provide the same utility level.
2. Typical utility function: One common form is the Cobb-Douglas utility function $$U(x,y) = x^a y^b$$ where $x$ and $y$ are quantities of two goods, and $a,b>0$.
3. To graph an indifference curve for a fixed utility level $U_0$, set:
$$x^a y^b = U_0$$
4. Solve for $y$:
$$y = \left(\frac{U_0}{x^a}\right)^{1/b} = U_0^{1/b} x^{-a/b}$$
5. This function shows that as $x$ increases, $y$ decreases to keep utility constant, typical of indifference curves.
6. Example: For $a=b=1$ and $U_0=1$, the equation simplifies to:
$$y = \frac{1}{x}$$
7. This hyperbola represents a typical indifference curve.
Final answer: The indifference curve for $U(x,y)=x^a y^b$ at fixed utility $U_0$ is
$$y = U_0^{1/b} x^{-a/b}$$.
For example, if $a=b=1$ and $U_0=1$, the curve is $y=1/x$.