Answer
$$\left(\frac{x}{2}\right)^{2}+\left(\frac{y}{4}\right)^{2}=1.$$
Work Step by Step
By observing Figure 15(B), we get that
$$ a=2, \quad b=4.$$
Plugging into the equation on page 692, we get:
$$\left(\frac{x}{2}\right)^{2}+\left(\frac{y}{4}\right)^{2}=1.$$
