The problem asks us to identify the type of curve represented by the polar equation $r = \frac{4}{1 + 2\sin\theta}$. If it is a conic, we must also determine its eccentricity.
2025/6/1
1. Problem Description
The problem asks us to identify the type of curve represented by the polar equation . If it is a conic, we must also determine its eccentricity.
2. Solution Steps
First, we need to rewrite the polar equation into the standard form of a conic section:
where is the eccentricity and is the distance from the focus (the pole) to the directrix.
We have . Comparing this to the standard form, we see that and . Therefore, , so .
Since , the conic section is a hyperbola.
3. Final Answer
The curve is a hyperbola with eccentricity .