use the polar function to answer the followin...
use the polar function to answer the following. fill in the table. r = 8 cos(4θ) type: line circle rose opens: petals: cycle: θ r π/6 π r = -7 sin(θ) type: line circle rose opens: petals: cycle: θ r π/3 π/2
Answer
# Explanation:
## Step1: Identify type of $r = 8\cos(4\theta)$
The general form of a rose - curve is $r = a\cos(n\theta)$ or $r=a\sin(n\theta)$. When $n$ is even, the number of petals is $2n$. Here $n = 4$, so it is a rose - curve.
Type: Rose; Petals: $2\times4 = 8$; Cycle: The period of $\cos(4\theta)$ is $\frac{2\pi}{4}=\frac{\pi}{2}$, so cycle is $\frac{\pi}{2}$.
When $\theta=\frac{\pi}{6}$, $r = 8\cos(4\times\frac{\pi}{6})=8\cos(\frac{2\pi}{3})=8\times(-\frac{1}{2})=- 4$.
When $\theta=\pi$, $r = 8\cos(4\pi)=8\times1 = 8$.
## Step2: Identify type of $r=-7\sin(\theta)$
The general form of a circle in polar coordinates is $r = 2a\sin(\theta)$ or $r = 2a\cos(\theta)$ centered at $(0,a)$ or $(a,0)$ respectively. For $r=-7\sin(\theta)$, it is a circle. The circle $r = - 7\sin(\theta)$ is centered at $(0,-\frac{7}{2})$ and opens downwards.
Type: Circle; Opens: Downwards; Petals: N/A; Cycle: The period of $\sin(\theta)$ is $2\pi$, so cycle is $2\pi$.
When $\theta=\frac{\pi}{3}$, $r=-7\sin(\frac{\pi}{3})=-7\times\frac{\sqrt{3}}{2}=-\frac{7\sqrt{3}}{2}$.
When $\theta=\frac{\pi}{2}$, $r=-7\sin(\frac{\pi}{2})=-7$.
# Answer:
| | $r = 8\cos(4\theta)$ | $r=-7\sin(\theta)$ |
|--|--|--|
| Type | Rose | Circle |
| Opens | N/A | Downwards |
| Petals | 8 | N/A |
| Cycle | $\frac{\pi}{2}$ | $2\pi$ |
| $\theta=\frac{\pi}{6},r$ | - 4 | N/A |
| $\theta=\pi,r$ | 8 | N/A |
| $\theta=\frac{\pi}{3},r$ | N/A | $-\frac{7\sqrt{3}}{2}$ |
| $\theta=\frac{\pi}{2},r$ | N/A | - 7 |