Polar Conversion 6A50Ed
1. **State the problem:** We are given two equations:
$$y = \frac{\sqrt{3x}}{3}$$
and
$$x^2 + y^2 = 12cx$$
We want to understand these equations and convert the Cartesian equation to polar coordinates.
2. **Recall the polar coordinate formulas:**
In polar coordinates, we use:
$$x = r\cos\theta$$
$$y = r\sin\theta$$
where $r$ is the distance from the origin and $\theta$ is the angle from the positive x-axis.
3. **Convert the circle equation to polar form:**
Substitute $x = r\cos\theta$ and $y = r\sin\theta$ into
$$x^2 + y^2 = 12cx$$
We get:
$$r^2 = 12c (r\cos\theta)$$
4. **Simplify the equation:**
$$r^2 = 12cr\cos\theta$$
Divide both sides by $r$ (assuming $r \neq 0$):
$$r = 12c\cos\theta$$
5. **Interpretation:**
This is the polar form of the circle equation. It represents a circle with radius depending on $\theta$.
6. **Analyze the first equation:**
$$y = \frac{\sqrt{3x}}{3}$$
This can be rewritten as:
$$y = \frac{1}{3} \sqrt{3x} = \frac{\sqrt{3}}{3} \sqrt{x}$$
This defines $y$ in terms of $x$ for $x \geq 0$.
7. **Summary:**
- The circle equation in polar coordinates is:
$$r = 12c\cos\theta$$
- The function $y = \frac{\sqrt{3x}}{3}$ is a curve defined for $x \geq 0$.
**Final answer:**
$$r = 12c\cos\theta$$